Restore spanner receiver, and add new codeowners

[dashpole]

Description

Reverts #35724.

The existing CODEOWNER had moved on. This adds myself as the sponsor of the component, and three members of the spanner team to ensure we don't have a single point of failure.

@dsimil @KiranmayiB @harishbohara11

New codeowners, please approve!

cc @codeboten

[dashpole]

lint failure appears unrelated:

Error: stanza/fileconsumer/attrs/attrs.go:44:6: SA4023: this comparison is always true (staticcheck)
		if err != nil {
		   ^
Error: stanza/fileconsumer/attrs/attrs.go:43:9: SA4023(related information): the lhs of the comparison is the 1st return value of this function call (staticcheck)
		err = r.addOwnerInfo(file, attributes)
		      ^
Error: stanza/fileconsumer/attrs/owner_windows.go:13:20: SA4023(related information): (*github.com/open-telemetry/opentelemetry-collector-contrib/pkg/stanza/fileconsumer/attrs.Resolver).addOwnerInfo never returns a nil interface value (staticcheck)
func (r *Resolver) addOwnerInfo(_ *os.File, _ map[string]any) error {

[songy23]

You may also want to add the new approvers to https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/cmd/githubgen/allowlist.txt if they are not yet OTel members https://github.com/orgs/open-telemetry/people

(This check only runs on mainline so you won't see CI failures in your PR)

[dashpole]

@songy23 done

[andrzej-stencel]

Are you planning to create a pull request for Releases repo to re-add the component to the Contrib distro?

[dashpole]

yep, i'll do that. It looks like it is currently referencing the 112 release, though, which doesn't include this receiver, so i'm not sure if it will be able to be merged right away.

[codeboten]

Thanks for volunteering to take on this component. Can you have a look at #29830 and #30370

[dashpole]

@codeboten filed #36112 to track.

[codeboten]

thanks @dashpole! much appreciated