Remove workflows related to helm and docker.

Not needed in this fork.

Remove workflows related to helm and docker.

Not needed in this fork.

Update changelog for v0.49.2 (prometheus-community#853)

Update changelog for v0.49.1 (prometheus-community#851)

Update changelog for v0.49.0 (prometheus-community#846)

Prepare for release v0.48.0-alpha (prometheus-community#809)

Prepare for release v0.47.0 (prometheus-community#806)

Prepare helm chart release 0.14.0 (prometheus-community#808)

Prepare changelog for v0.46.0-alpha. (prometheus-community#791)

Release helm chart 0.12.0 (prometheus-community#792)