refactor: added reinitializer and storage gap to `PluginRepo` and moved events to `IPluginRepo`

Description

[x] is upgradeable, but it doesn’t have a storage gap
[x] Why are the events VersionCreated and ReleaseMetadataUpdated in PluginRepo and not in the IPluginRepo Interface?
- we can move the events to the right place without changing the ERC-165 interface ID and updating the PluginRepoFactory
[x] We miss a test checking that function updateReleaseMetadata emits the ReleaseMetadataUpdated event
[x] Add an initializeFrom function to the contract. (see )
- check on DAO.sol how this function is supposed to work
- if we don’t need to re-initialize, then this function will be empty for now.

Task ID: OS-676

See the framework lifecycle in packages/contracts/docs/framework-lifecycle to decide what kind of change this pull request is.

[x] New feature (non-breaking change which adds functionality)
[ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

[x] I have selected the correct base branch.
[x] I have performed a self-review of my own code.
[x] I have commented my code, particularly in hard-to-understand areas.
[x] My changes generate no new warnings.
[ ] Any dependent changes have been merged and published in downstream modules.
[x] I ran all tests with success and extended them if necessary.
[ ] I have updated the CHANGELOG.md file in the root folder.
[ ] I have updated the DEPLOYMENT_CHECKLIST file in the root folder.
[ ] I have updated the UPDATE_CHECKLIST file in the root folder.
[ ] I have updated the Subgraph and added a QA URL to the description of this PR.