Previously, a PR's status page would only show the linked / related
PRs when `open`.
Since the relations between PRs remains useful, also make this
information available during staging and after merging.
Fixes#463
Because github materialises every labels change in the
timeline (interspersed with comments), the increasing labels churn
contributes to PRs being difficult to read and review.
This change removes the update of labels on PRs, instead the mergebot
will automatically send a comment to created PRs serving as a
notification that the PR was noticed & providing a link to the
mergebot's dashboard for that PR where users should be able to see the
PR state in detail in case they wonder what's what.
Lots of tests had to be edited to:
- remove any check on the labels of the PR
- add checks on the PR dashboard (to ensure that they're at least on
the correct "view")
- add a helper to handle the comment now added to every PR by the 'bot
- since that helper is needed by both mergebot and forwardbot, the
utils modules were unified and moved out of the odoo modules
Probably relevant note: no test was added for the dashboard
ACL, though since I had to explicitly unset the group on the repo used
for tests for things to work it looks to me like it at least excludes
people just fine.
Fixes#419
