[PM-18504] Enable SQL transaction log backup

[Mart124]

Hello,

🎟️ Tracking

bwdata/mssql/data/vault_log.ldf, which is the SQL transaction log file, grows indefinitely.

📔 Objective

This PR then adds the transaction log backup to the full backup, so that it is properly rotated, preventing it to grow.
It then fixes #648, with a better / safer approach than #3140.

🦮 User guidelines

If one wants to shrink the transaction log file, which may have grown unexpectedly (because not backed-up until now), the following SQL command will be needed (after 2 backups at least so that the end of the transaction log gets unused) :
use vault;
go
DBCC SHRINKFILE (vault_log);
go
It has not been added as a command to the backup script, as it is not considered as a regular maintenance one, but added a a guideline.

Thank you very much 👍

[bitwarden-bot]

Thank you for your contribution! We've added this to our internal Community PR board for review.
ID: PM-18504
Link: https://bitwarden.atlassian.net/browse/PM-18504

Details on our contribution process can be found here: https://contributing.bitwarden.com/contributing/pull-requests/community-pr-process.

[Mart124]

Hello @kspearrin,
As you reviewed previous PR on these file (a few years back now !), I would be glad if you could look at this one :)
Thank you very much 👍