Store: Remove version upgrades before 3.0

According to this discussion, it has been suggested that we should clean up the storage upgrades before 3.0, as nodes should be following this version since octez v.16.0 onwards.

What

Why

How

Manually testing the MR

CI green + successful run of an octez-node.

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR