Add link to all types of tasks within single project
Rework task submission form

- It is possible now to submit tasks to specified project.
- All the extra fields which are not interesting got us
  are now hidden.
- Default visibility is User (maybe we might want
  "Everyone" in fact)?
- Only Administrators are able to edit issues by
  default.
- Links to bug report are available from welcome page
  and from project's maniphest page.
- Added file with report bug guidelines. Currently
  just copy-pasted it from project.b.o, some style
  tweaks are welcome.
Update migration steps with info from test run of importing to developer.blender.org.
Update welcome.html with correct project IDs.
Tweaks to welcome and bug report pages, making them a bit prettier and hopefully
more clear.
Use blender.org's favicon
Reshuffle order of builtin queries
Add buildbot and developer wiki links in the menu.
Better looks and css for welcome.html. For reference, __celerity_resource_map__.php
was updated with this command.

./scripts/celerity_mapper.php --with-custom webroot
Tasks: don't force particular policy in the code here, let it be defined by the
default policies configured for maniphest.
Tweaks to maniphest

- Remove quick links to create tasks, now only
  "Report Bug" to a specified project is allowed.
- Added 'Addons' to list of 'always visible'
  in navigation bar projects.
Revert changes in AphrontFormPolicyControl.php

After recent Brecht's commit they're not needed.

Euh, didn't notice policies could be edited in configuration :(
Tweaks to page and mail titles

- Welcome page will now have title "Blender Foundation: Welcome",
  the same as in old projects.b.o.
- Mail will be sent from name of BF, not phabricator, seems to
  be quite logical to do.
Added script which rebuilds gitadmin configuration

It generates new gitosis.conf and public key files.
Actual commit to repo would likely be done with a
wrapper script which will run in cron.
Missed this in previous 'revert changes' commit
Made 'pushable' of repository editable for non-hosted repos as well
Rework gitosis config generator to use pushable settings from repository
Whitespace cleanup