Draft: Split error tracking setting from telemetry into GDK setting gdk.crash_report

What does this merge request do and why?

This MR moves error tracking functionality from GDK::Telemetry into own module GDK::CrashReport.

It also creates a new GDK setting gdk.crash_report.<enabled|username>.

Users with telemetry setting enabled will automatically send crash reports (gdk.crash_report.enabled = 'always') with the stored username.

Contributes to #2086.

Draft?

• Remove gdk crash command
• Add docs

How to set up and validate locally

gdk config set telemetry.enabled false
gdk config set telemetry.username ''
gdk crash
:crashed
Do you want to send crash report to GitLab?
(see https://... how this data is processed)
- yes, (a)lways send crash reports
- (y)es, send crash report only once
- (n)o, don't send crash report this time
- no, n(e)ver send crash report
- (v)iew report contents

Impacted categories

The following categories relate to this merge request:

• gdk-reliability - e.g. When a GDK action fails to complete.
• gdk-usability - e.g. Improvements or suggestions around how the GDK functions.
• gdk-performance - e.g. When a GDK action is slow or times out.

Merge request checklist

• This change is backward compatible. If not, please include steps to communicate to our users.
• Tests added for new functionality. If not, please raise an issue to follow-up.
• Documentation added/updated, if needed.
• Announcement added, if change is notable.
• gdk doctor test added, if needed.
• Add the ~highlight label if this MR should be included in the CHANGELOG.md.