Migrate audit list to gravity.db database table

[DL6ER]

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What does this PR aim to accomplish?:

Migrate the list of audited domains into the gravity.db database

How does this PR accomplish the above?:

Well, see above.

What documentation changes (if any) are needed to support this PR?:

The database documentation needs to be extended. This will be done in a follow-up PR.

[AzureMarker]

We should add a timeout to the SQLite commands we run.

  [✓] Restarting pihole-FTL service...
Error: near line 1: database is locked
Error: near line 8: database is locked
  [i] Migrating content of /etc/pihole/auditlog.list into new database

  [✗] Unable to truncate domain_audit database /etc/pihole/gravity.db
  Error: near line 1: no such table: domain_audit