Display location for new strings

Description

Display the location of new strings in the string freeze break GitLab notifications. To do that we need to pass whole objects around instead of just the strings, to be able to generate the markdown we want.

Part of the change is also to get rid of the custom PO file parser and use the translate-toolkit parser instead.

Fixes Freeze break notification: link to files (#372 - closed).

Migration and compatibility

• The merge request DOES NOT update the models. If it does, it is needed to migrate the database after merging, add the label ~"Database migrations"
• The merge request DOES NOT break the compatibility.

Related documents

• translate-toolkit API Reference
• GitLab Flavored Markdown

TODO

Before being accepted, any merge request must fulfill the following requirements:

• Check PEP8 writing style as described in CONTRIBUTING.md.
• Ensure existing tests are still working properly.
• Features have been tested.
• You used your best English for every translatable string 😀.
• You marked every translatable string with gettext, blocktrans and/or trans.
• Ensure that there is no side effect in files: changes are only related to one, and only one feature.
• Ensure that no file has been removed by accident.
• Document you API, as well as the behavior, if needed, in docs.
• Ensure the commit history is “clean enough” (this means no extra merge commits, etc − try to rebase to clean it if possible).
• Ensure pipeline succeeds.

Deploy Notes

N/A

Steps to Test or Reproduce

1. Override your local worktree with the one from the remote branch:

   git reset --hard kcommaille/potdiff

2. Launch the Damned Lies server,
3. Have/Add a GitLab project in string freeze,
4. Trigger a stats update after adding a few strings in the project.

Impacted Areas in Application

Stats