Set reasonable defaults when displaying remote repository URIs.

Summary: Show SSH user on git-over-ssh repositories and hide both username and password for other repos.

Test Plan: View repository details page in diffusion, Clone URI should appear with a username (taken from repo config) and any http(s) repos should be without usernames.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley

CC: Korvin, epriestley, aran

Maniphest Tasks: T4147

Differential Revision: https://secure.phabricator.com/D7631
Fix issue when paging Applications

Summary: See <https://github.com/facebook/phabricator/issues/450>.

Test Plan: See GitHub issue.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Differential Revision: https://secure.phabricator.com/D7627
Drydock blueprint for preallocated remote hosts

Summary:
This adds a Drydock blueprint for preallocated, remote hosts.  This will be used by the Harbormaster interface to allow users to specify remote hosts that builds can be run on.

This adds a `canAllocateResource` method to Drydock blueprints; it is used to detect whether a blueprint can allocate a resource for the given type and attributes.

Test Plan:
Ran:

```
bin/drydock lease --type host --attributes remote=true,preallocated=true,host=192.168.56.101,port=22,user=james,keyfile=,path=C:\\Build\\,platform=windows
```

and saw the "C:\Build\<id>" folder appear on the remote Windows machine.  Viewed the lease and resource in Drydock as well.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley

CC: Korvin, epriestley, aran, jamesr

Maniphest Tasks: T4111

Differential Revision: https://secure.phabricator.com/D7593
Add "allow null" and username hinting to the Passphrase credential control

Summary:
Ref T4122.

  - For Diffusion, we need "allow null" (permits selection of "No Credential") for anonymous HTTP repositories.
  - For Diffusion, we can make things a little easier to configure by prefilling the username.

Test Plan: Used UIExample form. These featuers are used in a future revision.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T4122

Differential Revision: https://secure.phabricator.com/D7624
Add "PassphraseKey" classes for code which needs to actually use credentials

Summary: Ref T4122. These classes provide typed, checked access to credentials, so you can say "give me this password, and throw if anything is funky".

Test Plan: Used in next revision.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T4122

Differential Revision: https://secure.phabricator.com/D7625
Add an edge between Passphrase credentials and objects which use them

Summary: Ref T4122. Add an edge to keep track of where a credential is used, and show it in the UI.

Test Plan:
See "Used By":

{F84099}

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T4122

Differential Revision: https://secure.phabricator.com/D7628
Migrate repositories to use Passphrase for credential management

Summary: Fixes T4122. Ref T2230. Instead of storing credentials on each repository, store them in Passphrase. This allows easy creation/management of many repositories which share credentials.

Test Plan:
  - Upgraded repositories.
  - Created and edited repositories.
  - Pulled HTTP and SSH repositories.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T2230, T4122

Differential Revision: https://secure.phabricator.com/D7629
Add UI for defining repository mirrors

Summary:
Ref T4038. This adds everything except the actual pushing part for mirrors.

This isn't the most beautiful or sophisticated UI, but I want get the authoritative repositories self-hosted and get users beta-ing hosting as soon as possible. We can do transactions, etc., later on.

Test Plan: See screenshots.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T4038

Differential Revision: https://secure.phabricator.com/D7632
Actually push to mirrors

Summary: Fixes T4038. Push repositories to mirrors.

Test Plan: Created a functional mirror of a local: https://github.com/epriestley/poems

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T4038

Differential Revision: https://secure.phabricator.com/D7633
Document and remove some scary warnings from repository hosting

Summary: Fixes T2230. This isn't a total walk in the park to configure, but should work for early adopters now.

Test Plan: Read documentation, browsed UI.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T2230

Differential Revision: https://secure.phabricator.com/D7634
Fix a minor issue with editing Credential policies

Also, test repository self-hosting.

Auditors: btrahan
Make `ssh-connect` more robust against known_host issues

I think the daemon is choking on this, prevent it from failing.

Auditors: btrahan
Fix an issue where SSH protocols would check legacy credentials

Missed this while grepping. We should use SSH purely based on protocol.

Auditors: btrahan
Fix an issue with editing policies in Phlux.

Mostly, this is testing the auto-mirroring stuff.

Auditors: btrahan
Add some light padding to code views.

Summary: Source code output currently juts up against the border of its container, making the first and last lines harder to read, this diff adds some padding inside.

Test Plan: {F79908} {F79907}

Reviewers: epriestley, chad, #blessed_reviewers

Reviewed By: chad

CC: chad, Korvin, epriestley, aran

Differential Revision: https://secure.phabricator.com/D7542
Fix error creating repository from file:/// location, due to uninitialized variable.

Summary: This was broken in rP51fb1ca16d7f.

Test Plan: Imported a repository with file:/// location, it worked.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley

CC: Korvin, epriestley, aran

Differential Revision: https://secure.phabricator.com/D7636