Document how to load new Settings metadata

Add example of PSR-4 autoloading within extensions

Typo

Fix broken link

Use IDNUMBER instead of N for easier reading

**N** does not render as bold in the code text, so replace with easier read IDNUMBER.
Fix incorrect >**N** in some URLs.

Improve docs for publishing an extension.

Previously it read that you only needed to create a release on *subsequent* releases, but my experience was that the extension was not available until the initial release was made also. Rewrote to clarify this.

Also made a few additions to inline docs on the create a release node page. These can be recorded over in CiviCRM.org website repo via Features.

Refs #323.

Add another code construct (Civi::resources)

Update mkdocs.yml

Typo

issue-tracking.md - Mutiple updates

 1. The prefix is useful to know.
 2. The full list contains distractions and makes the page feel less authoritative.
 3. New/future projects aren't likely to go into JIRA.

The `HR` project in issues.civicrm.org was used for CiviHR 1.0-1.4.  When
the project was transferred to Compucorp, they moved issue-tracking to a
private system.  The JIRA `HR` project only exists for historical purposes.

The example command works if you've manually installed the `hub` with all
the suggestions in upstream's guide -- specifically, they suggest aliasing
`git`==`hub`.  However, in `civi-download-tools`, we download the `hub`
command but can't setup the alias.

Documenting commands as `hub <foo>` should make them more robust/portable to
more configurations.

hook_civicrm_angularModule - Add basic doc for `settings`

Add in some documentation on PHPIDS

Clarify that PHPIDS is not just about inputs which are saved to the
database, but actually all inputs (e.g. GET params) even ones that
aren't saved to the DB.

Migrate Token Documentation

ref:
https://docs.civicrm.org/dev/en/latest/documentation/style-guide/#describing-the-civicrm-user-interface

Update more wiki urls