[extensions/observer/cfgardenobserver] Implement cfgardenobserver

[tomasmota]

Description:
First Component PR: #33727
This is the second PR for adding the cfgardenobserver, with the first suggested implementation. There are definitely some decisions made that require feedback, such as adding the CloudFoundry application labels to the Endpoint labels, and the decision to use the Container EndpointType at all.

Link to tracking Issue: #33618

Testing: Unit testing of config and extension

Documentation: Updated readme with new configuration and endpoints

[crobert-1]

Generated code is out of date, please run "make generate" and commit the changes in this PR.

[crobert-1]

Mostly just nits.

I haven't gotten a chance to look through tests yet, I wanted to get a review out sooner rather than later. Hope it's helpful 👍

[tomasmota]

Mostly just nits.

I haven't gotten a chance to look through tests yet, I wanted to get a review out sooner rather than later. Hope it's helpful 👍

I appreciate that, think I have addressed all the issues.

Regarding the context in the struct, I'd like to know if you think what I did (just keeping a channel) is ok, or if I might be missing some need for a context.