Add changes to project MR settings to audit events

We should also track all project settings changes, including those in "Merge request settings". These include:

• Changing the merge method strategy for a project
• Changing the default MR template
• Changing settings:
  • Merge request approvals
  • Only allow merge requests to be merged if the pipeline succeeds
  • Only allow merge requests to be merged if all discussions are resolved
  • Automatically resolve merge request diff discussions when they become outdated
  • Show link to create/view merge request when pushing from the command line