Add Trello integration

While working on an issue related to the Asana integration I thought we could also implement a similar feature integrating with Trello.

Proposed feature details:

The Trello integration adds commit messages as comments to Trello cards. Once enabled, commit messages are checked for Trello card URLs (for example, https://trello.com/c/FHNuzF7m) or card IDs starting with # (for example, #FHNuzF7m). Every card ID found gets the commit comment added to it.

You can also mark a Trello card as done with a message containing: fix #FHNuzF7m. You can use either of these words:

• fix
• fixed
• fixes
• fixing
• close
• closes
• closed
• closing

I have opened a draft MR that accomplishes the above: !152073

Screen_Recording_2024-05-07_at_20.21.53

TODO:

• Upload Trello image for the integrations page
• Create files for metrics config/metrics/counts_all

cc @m_frankiewicz, @wortschi