move sql files in the python package and update tests according to D538

Also depends on swh-storage's swh-storage!99 (closed).

This refactoring also requires a small change in vault's swh-schema.sql: create the dbversion table only if needed, otherwise this sql cannot be executed without error on the top of storages' db schema.

Related to swh-storage#1265 (closed).

Test Plan

tests should pass provided that swh-core!16 (closed) and swh-storage!99 (closed) are applied.

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Migrated from D542 (view on Phabricator)

Some references in the commit message have been migrated:

• T1265 is now swh-storage#1265 (closed)

Some references in the commit message have been migrated:

• T1265 is now swh-storage#1265 (closed)

Merge request was accepted

approved this merge request

Merge request was merged

closed