Remove uptest related metadata from the example manifests published in the marketplace

[ulucinar]

What problem are you facing?

How could Uptest help solve your problem?

We publish some metadata related to uptest in the example manifests in the Upbound marketplace. An example is here: https://marketplace.upbound.io/providers/upbound/provider-aws/v1.4.0/resources/acm.aws.upbound.io/Certificate/v1beta1

There are also template variable expressions which may confuse the users of the Upbound marketplace.

For instance, please note the upjet.upbound.io/manual-intervention annotation in the first example manifest. Such metadata is required while testing these manifests with uptest but are not useful in other contexts (the associated MR controller does not use them).

We may consider removing such metadata/templating expressions before publishing these example manifests to the marketplace with updoc.

[ulucinar]

cc. @turkenf. We still need to agree on the timeline.

[turkenf]

We have cleaned uptest specific codes/placeholders with the cleanupexamples tool with the latest provider releases. As mentioned in this TODO comment, we also want to clean the UPTEST_DATASOURCE placeholders. We should also clean up the meta.upbound.io/example-id: that @ytsarev mentioned, as it is not used for its intended purpose and confuses users.