Add labels for needs-triage, fix-now, fix-later and won't-fix to Github repositories

[jmcook1186]

Sub of #651

What

Add labels for needs-triage, fix-now, fix-later and won't-fix to Github repositories

Why

As a core dev I want an easy way to tag bugs with their post-triage status. As a user, I want to quickly and clearly see the status of active bug reports. This improves our internal process for tracking bugs because we can see at a glance what was the outcome from a bug triage and whether a bug requires attention. It also improves our public facing communications because users can quickly tell whether a bug is being worked on, scheduled to be worked on, or whether they should not expect any action to be taken.

Context

We can apply three simple labels signalling the status of a bug report after it has been triaged: fix-now for urgent bugs, fix-later for non-urgent bugs, and wont-fix for bug reports that we will not work on because it is benign, or the report is somehow incorrect.

Prerequisites
None

Statement of Work

• add four new labels to all IF repositories (if, if-plugins, if-unofficial-plugins, if-plugin-template)
• update bug report documentation to include label definitions

Acceptance Criteria

• labels needs-triage, fix now, fix-later and wont-fix are added to if, if-plugins, if-unofficial-plugins and if-plugin-template repositories
• Bug report documentation describes the new labels and their intended usage

Reviewer
@manushak

[jmcook1186]

@zanete - labels added for all repositories via the gh CLI (no PR)
documentation updated in #663