ci: add changelog generator and commitlint

[oldgiova]

Added release-please and git cliff to generate changelogs and Github Releases

Ticket: QA-776

Added optional commit linter: commitlint.

• Sample commit linting failure
• Sample commit linting ok

[mzedel]

I just assume this will be merged after https://github.com/mendersoftware/mendertesting/pull/340

[oldgiova]

I just assume this will be merged after mendersoftware/mendertesting#340

Yes, sorry, I forgot to specify it

[oldgiova]

Also added commitlint; please review again

[kjaskiewiczz]

General question - do we need to group changelogs by services (if I understand correctly this is what we are doing/trying to do with current git cliff configuration)?

[oldgiova]

General question - do we need to group changelogs by services (if I understand correctly this is what we are doing/trying to do with current git cliff configuration)?

We have to define it. The very same changelog file will populate also the documentation website. What we're achieving here, is also what costumers will see on the doc website.

Right now we're creating a single CHANGELOG.md file with group by groups, then group by scope (service). For example:

# v3.8.0

## Bug fixes
### Deployments
- fix a thing
- fix another thing

### Auditlogs
- fix here
- fix there
- fix everywhere

## Features
### Deployments
- feature here
- feathre there

### Deviceconnect
- feature here
- feature there