COCOS-192 - Add support for attested TLS

[danko-miladinovic]

What type of PR is this?

This feature is an enhancement for attested TLS. The idea is to have the attestation fetched and forwarded as a TLS extension. This way, we can guarantee the freshness of the evidence.

What does this do?

Adds custom TLS extensions that transfer the nonce and the attestation report between the client (CLI) and server (Agent).

Which issue(s) does this PR fix/relate to?

• Resolves #192

Have you included tests for your changes?

No, the process is tested as before. There is no need for new tests.

Did you document any new/modified feature?

No, the documentation will be added upon completion.

Notes

This PR is still a draft.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 17.88793% with 381 lines in your changes missing coverage. Please review.

Please upload report for BASE (main@f6a93fe). Learn more about missing BASE report. Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/atls/atlsLIstener.go	0.00%	273 Missing :warning:
pkg/attestation/quoteprovider/sev.go	43.85%	53 Missing and 11 partials :warning:
pkg/clients/grpc/connect.go	10.00%	27 Missing :warning:
internal/server/grpc/grpc.go	59.09%	6 Missing and 3 partials :warning:
manager/backend_info.go	33.33%	3 Missing and 1 partial :warning:
cli/attestation.go	0.00%	1 Missing and 1 partial :warning:
cli/backend_info.go	80.00%	0 Missing and 1 partial :warning:
cli/cache.go	75.00%	0 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #279 +/- ## ======================================= Coverage ? 56.61% ======================================= Files ? 57 Lines ? 4585 Branches ? 0 ======================================= Hits ? 2596 Misses ? 1715 Partials ? 274 ```

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