Add changelog

[ales-tsurko]

We should considered wether the changelog should be generated from the commit history or modified manually.

In case of manual logging we need to configure CI/CD so that it checks the changelog updataed on new release (or, for example, branch merge).

In case of generated changelog, we should prevent it to be messy and configure CI/CD, which would check the style (for example, merge commit messages). Also, we should have strict guideline related to commit messages or anything else which would go into the log.

We should avoid to switching conventional commits for that, as the changelogs generated from repos sticked to this practice use to have messy changelogs.

For the changelog itself, we should follow these guidelines.

[ales-tsurko]

In discussion we considered doing it this way:

• the changelog will be generated in accordance to these guidelines
• the records in changelog are generated from merge commits only
• we need to add validation of merge commits messages to make them suitable for the changelog and to restrict how the message can look like
  • the validation should allow only valid merge commit message to merge
• the changelog will be generated only on testnet release (and on mainnet in the future)
  • the release will have semantic versioning
  • we should change docker image tagging for testnet and devnet like this:
    • instead of <netname>-<date>-<timestamp> it should be <netname>-nightly-<date>-<timestamp> (for ex., devnet-nightly-28032024-142503)
    • instead of <netname>-latest for current release which we make for images when we push changes to git branches, we need <netname>-nightly-latest (for ex., devnet-nightly-latest)
    • for actual release we need to push an image which should look like <netname>-<version> and <netname>-latest (for ex., testnet-v0.1.1 and testnet-latest)