feat: introduce ConfidentialComputing

[bshaffer]

see b/277761363

This was generated using #5861 and a script to run owlbot (https://gist.github.com/bshaffer/ab2faa3933ff0c083ea3ae025583c6a8):

# run the command to generate the basic file components
$ dev/google-cloud add-component google/cloud/confidentialcomputing/v1/service.proto

# run a script to generate all the protobuf and gapic classes using owlbot
# and copy them to the right lications
$ bash generate-gapic-services.sh ConfidentialComputing

[snippet-bot]

Here is the summary of changes.

You are about to add 4 region tags.

• ConfidentialComputing/samples/V1/ConfidentialComputingClient/create_challenge.php:25, tag confidentialcomputing_v1_generated_ConfidentialComputing_CreateChallenge_sync
• ConfidentialComputing/samples/V1/ConfidentialComputingClient/get_location.php:25, tag confidentialcomputing_v1_generated_ConfidentialComputing_GetLocation_sync
• ConfidentialComputing/samples/V1/ConfidentialComputingClient/list_locations.php:25, tag confidentialcomputing_v1_generated_ConfidentialComputing_ListLocations_sync
• ConfidentialComputing/samples/V1/ConfidentialComputingClient/verify_attestation.php:25, tag confidentialcomputing_v1_generated_ConfidentialComputing_VerifyAttestation_sync

---

This comment is generated by snippet-bot.
If you find problems with this result, please file an issue at:
https://github.com/googleapis/repo-automation-bots/issues.
To update this comment, add snippet-bot:force-run label or use the checkbox below:

• Refresh this comment

[vishwarajanand]

LGTM