Fix push trigger in PR use case, add flow for maintenance of main branch

[mczyz-antmicro]

• [x] The PR review use case shouldn't be triggered on push to main, thus change in *-send.yml.
• [x] Enabled checking of branch main with a standard ruleset
• [ ] Add exclude files
• [ ] Add presentation layer of fails

[mczyz-antmicro]

72 supercedes these changes and they are no longer required.