Add otelcol-config

[echlebek]

This commit adds otelcol-config, a tool designed to be used for configuration otelcol-sumo installations.

The tool will mainly write values to conf.d/00-otelcol-config-settings.yaml, conf.d/99-otelcol-config-overrides.yaml, and link and unlink specific configuration files in conf.d from conf.d/available.

[sumo-drosiek]

Awesome! Do we consider to move other functionality from the install script as well? (checking otel version, verifying what is the latest one and so on?)

[swiatekm]

Shouldn't this live in the packaging repo?

[amdprophet]

Awesome! Do we consider to move other functionality from the install script as well? (checking otel version, verifying what is the latest one and so on?)

I think this falls outside of the existing scope of otelcol-config. We're moving away from using curl in the shell script all together and instead will be using packaging repositories where the latest version can be determined from package managers (e.g. yum/dnf, apt, etc.)

Shouldn't this live in the packaging repo?

The otelcol-config binary will be packaged with the otelcol-sumo binary. Its features are tightly coupled with the features of otelcol-sumo. I believe it's best to keep it in the collector repository as a result and use the same versioning as the otelcol-sumo binary.