* Motivation:

Make use of more common GitHub Actions migration workflows and repository style changes.

Modifications:

* Unit tests workflows run redis in a separate services container to speed up unit tests
* Introduce `main.yml` which runs workflows on each commit to main and periodically to catch any regressions in merges or from upstream.
* Remove the docker files which are no longer used and contained outdated pipelines.
* Add Cxx interoperability checks

Result:

More in common with other GitHub Actions adoptions.

* disable strict concurrency

Update the release.yml file with the latest label changes

### Motivation:

Some errors do not show up in debug builds. Enabling release mode builds
improves the CI coverage.

### Modifications:

Enable release mode builds for pull requests and scheduled builds on
main.

### Result:

Improved CI coverage.

### Motivation:

Right now, the nightly CI is failing due to the package relying on old
decommissioned Swift toolchains (dev toolchains for 6.0).

### Modifications:

Updated the CI setup to be Swift 6.0+, bumped the tools version, but
kept the language mode to 5 for now.

Bumping of language mode from 5 to 6 can be done in a separate PR, this
PR is mainly to unblock nightly CI.

### Result:

Fixes nightly CI.