Improve the Accounts Template notes in YAML files.

- Improve the wording and grammar of template notes.
- Fix formatting and/or wording for a few of the default
  templates.
Fix typo on landing.yaml
Implement thread `format` field

Thread entries now have a flexible `format` specification, which allows the
system to save the format alongside the original text. This allows the
system not to have to convert everything to HTML when storing in the
database
thread: Implement format for Thread::setBody()
Honor thread body format in PDF export
Use strongly typed ThreadBody instances for output
Hide inline attachments on PDF output
Retroactively add the `format` column to ticket_thread

This will make upgrades from osTicket < 1.8.0 substantially faster and more
reliable, considering that the previous ticket threads will not need to be
explicitly converted to html.
Relax detection of images for strip detection

It is perfectectly fine to have an image cited in an HTML body similar to:

<img width=909 height=302 src=cid:image002.jpg@01CF5426.BF5A72A0 alt=image>

Which may or may not have quoted @src attribute, and may very well have an
at sign (@) somewhere in the attribute text. The previous regular expression
would not match such a @src attribute.
Add user account status class
Show user status on the user listing table
Merge pull request #772 from greezybacon/issue/relax-stripped-cid-detect

Reviewed-By: Peter Rotich <peter@osticket.com>
Add abstract ::display method to ThreadBody
Merge pull request #757 from greezybacon/feature/thread-format

Reviewed-By: Peter Rotich <peter@osticket.com>
Move organization support from UserAccount to User model.

Previously we required an account to associate a user to an organization.
Support unified remote user directory search

Support searching both staff and user backends via a common interface.
Add users to organization

Support adding existing or new users while on organization page.
Fixup multiple download hovers on inline images
Merge pull request #745 from beckonandmuse/issue/template-notes

Improve the Accounts Template notes in YAML files.

Reviewed-By: Jared Hancock <jared@osticket.com>
Add remote user

Support adding remote user to an organization
Merge pull request #774 from protich/feature/org-add-user

Add users to organization

Reviewed-By: Jared Hancock <jared@osticket.com>