feat(solana): upgradability

[cernicc]

Description

This PR introduces the upgradability of the Solana relay program. It adds versioning of accounts and reserves bytes for future fields. The suggested approach was specified in the solana-upgradability adr. Specifically the State Design with Reserved Space and Version-Aware Instructions chapters.

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• Linked to GitHub issue with discussion and accepted design, OR link to spec that describes this work.
• Wrote unit and integration tests.
• Added relevant natspec and godoc comments.
• Provide a conventional commit message to follow the repository standards.
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• Review SonarCloud Report in the comment section below once CI passes.

[mergify]

⚠️ The sha of the head commit of this PR conflicts with #768. Mergify cannot evaluate rules on this PR. ⚠️

[cernicc]

The continuation of the PR #768 . I had to create a new one because the branch was moved to a different remote.

[srdtrk]

Lgtm. I left a quesiton about the tests