Improve CI scalability

[gchristov]

What does this pull request change?

This PR removes the per-service CI workflows in favor of one flow which detects which services have changed and runs relevant actions.

How is this change tested?

With existing checks.

---

Writing Kotlin Multiplatform tests

[pulumi]

🍹 The Update (preview) for gchristov/thecodinglove-statistics/prod was successful.

Resource Changes

    Name                       Type                            Operation
~   statistics-service         gcp:cloudrunv2/service:Service  update
~   statistics-service-binary  docker:index/image:Image        update

[pulumi]

🍹 The Update (preview) for gchristov/thecodinglove-slack-web/prod was successful.

Resource Changes

    Name                      Type                            Operation
~   slack-web-service-binary  docker:index/image:Image        update
~   slack-web-service         gcp:cloudrunv2/service:Service  update

[pulumi]

🍹 The Update (preview) for gchristov/thecodinglove-self-destruct/prod was successful.

Resource Changes

    Name                          Type                            Operation
~   self-destruct-service         gcp:cloudrunv2/service:Service  update
~   self-destruct-service-binary  docker:index/image:Image        update

[pulumi]

🍹 The Update (preview) for gchristov/thecodinglove-slack/prod was successful.

Resource Changes

    Name                  Type                            Operation
~   slack-service-binary  docker:index/image:Image        update
~   slack-service         gcp:cloudrunv2/service:Service  update