feat: make space2share migration repeatable

[micbar]

Description

Adds opencloud shares migrate to re-run a jsoncs3 share manager migration by name, whether or not it has run before.

Main use: opencloud shares migrate import_space_members re-imports the grants of every project space into the share manager, e.g. after space members were written as storage grants outside OpenCloud. The import is additive, so re-running it is safe.

• --list shows the available migrations
• --timeout limits the run (default 30m)

Builds on opencloud-eu/reva#864 (already in main via #3685).

[codacy-production]

Up to standards ✅

🟢 Issues 0 issues

Results:
0 new issues

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🟢 Metrics 19 complexity

Metric	Results
Complexity	19

View in Codacy

🟢 Coverage 0.00% diff coverage · -0.01% coverage variation

Metric	Results
Coverage variation	✅ -0.01% coverage variation (-1.00%)
Diff coverage	✅ 0.00% diff coverage

View coverage diff in Codacy

Coverage variation details

	Coverable lines	Covered lines	Coverage
Common ancestor commit (84e10b3)	91169	22411	24.58%
Head commit (db4ad0f)	91247 (+78)	22423 (+12)	24.57% (-0.01%)

Coverage variation is the difference between the coverage for the head and common ancestor commits of the pull request branch: <coverage of head commit> - <coverage of common ancestor commit>

Diff coverage details

	Coverable lines	Covered lines	Diff coverage
Pull request (#3669)	85	0	0.00%

Diff coverage is the percentage of lines that are covered by tests out of the coverable lines that the pull request added or modified: <covered lines added or modified>/<coverable lines added or modified> * 100%

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[micbar]

Needs opencloud-eu/reva#864