Support an easier way for users to include OpenTelemetry components into Alloy

[ptodev]

Request

If a user wishes to include their own component into Alloy and then to run it as an OTel Collector distribution, then they'd need to:

1. Fork Alloy
2. Include an otelcol component
3. Add converters so that Alloy can translate OTel YAML into Alloy syntax
4. Run Alloy with the --config.format=otelcol command line argument

This process has a lot of friction. The upstream Collector offers the OpenTelemetry Collector Builder (OCB) as a way to do this more easily. It'd be worth looking into creating similar tooling for Alloy, or reusing the existing OCB tool for the purpose of adding components into Alloy.

Use case

A core principal of an OTel Collector Distribution is the ability for a user to add their own custom components. It'd be good to make this as easy as possible for Alloy users.

In particular, it would be good to not ask users to fork Alloy. One could argue that OCB is also creating a fork, but because it's very automated it seems to be a more acceptable solution.