Sqlite auto rollback

[Alenar]

Content

This PR add a light layer to easily open, commit, and rollback SQLite transactions.

This is done by adding a Transaction struct to mithril-persistence that:

• wrap a borrowed SQLite connection.
• define three public methods: begin (the constructor), commit and rollback.
• commit and rollback method move self, meaning that using either of them remove the transaction of the current scope: the compiler won't allow to use several commit or rollback on the same transaction.
• Implement Drop to automatically rollback the transaction when it goes out of scope if it was still active.

Also a begin_transaction extension method is added to the sqlite transaction so they can be created without needing to import the new type.

Pre-submit checklist

• Branch
  • [x] Tests are provided (if possible)
  • [x] Crates versions are updated (if relevant)
  • [x] Commit sequence broadly makes sense
  • [x] Key commits have useful messages
• PR
  • [x] No clippy warnings in the CI
  • [x] Self-reviewed the diff
  • [x] Useful pull request description
  • [x] Reviewer requested

Comments

While this system make using SQLite transactions easier it should not be used on our main SQLite database until we implement a connection pool system instead of sharing a global connection. Else we would be at risk of opening a transaction when one was already opened leading to at minimum an error or at worst a crash.

Issue(s)

Closes #1741

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Test Results

    3 files  ±0     43 suites  ±0   8m 35s :stopwatch: +8s 1 035 tests +6  1 035 :white_check_mark: +6  0 :zzz: ±0  0 :x: ±0  1 133 runs  +6  1 133 :white_check_mark: +6  0 :zzz: ±0  0 :x: ±0 

Results for commit 12576161. ± Comparison against base commit f5097f0a.

:recycle: This comment has been updated with latest results.