Open thread that needs to be resolved when notify job runs

Changes introduced

When there are modified DSIDs:

• notify_changes job creates a thread instead of a comment which needs to be resolved. This means that someone would actively have to resolve the thread before proceeding with the merging
• automatic merging of MR is disabled

This makes it impossible to set "merge when pipeline succeeds" in requests which modify existing DSIDs, which will hopefully make people more careful with merging.

Tests

1. Commit with [skip modfiles] and immediately set MR to merge after pipeline succeeds

2. MR reassigned by CI and automatic merging is disabled

No issue arises when someone does not have automatic merging enabled.

Issues resolved

Closes #206 (closed)

@mgignac I will merge this now - sorry for the spam emails.