feat: use direct c8y connection for c8y-remote-access-plugin

[rina23q]

Proposed changes

Remove the c8y-remote-access-plugin connection dependency on the c8y local proxy which is launched by the tedge-mapper-c8y service. This is part one of the large ticket (#2859) which looks at creating the remote access connection which is fully independent to the tedge-mapper-c8y service, thus allowing the user to execute tedge reconnect c8y without the remote access connection from being dropped.

Note

Prior to the c8y local proxy feature, the c8y-remote-access-plugin did use a direct connection to Cumulocity IoT, however the implementation was switch to use the local proxy which adds an additional connection dependency on the tedge-mapper-c8y (e.g. if you restart the tedge-mapper-c8y, the local proxy will also restart thus stopping the connection). This PR does not change the fact that there is still a process dependency between the spawned c8y-remote-access-plugin instance and the tedge-mapper-c8y service, however this will be addressed via #3007

The PR is based on reverting the c8y local proxy commit: 845480e

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Improvement (general improvements like code refactoring that doesn't explicitly fix a bug or add any new functionality)
• Documentation Update (if none of the other choices apply)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Paste Link to the issue

#2859

Use a direct connection to the Cumulocity IoT URL instead of using the local c8y proxy service (as the service is maintained by the tedge-mapper-c8y service) - (technically this will be reverting the change where we switched to using the local c8y proxy)

Checklist

• I have read the CONTRIBUTING doc
• I have signed the CLA (in all commits with git commit -s)
• I ran cargo fmt as mentioned in CODING_GUIDELINES
• I used cargo clippy as mentioned in CODING_GUIDELINES
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

Further comments

[github-actions]

Robot Results

✅ Passed	❌ Failed	⏭️ Skipped	Total	Pass %	⏱️ Duration
478	0	2	478	100	1h11m13.032927999s

[didier-wenzek]

@jarhodes314 Can you please review this PR. Thanks

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 35 lines in your changes missing coverage. Please review.

Project coverage is 78.0%. Comparing base (1c68fab) to head (2d897d3).
Report is 15 commits behind head on main.

Additional details and impacted files

Files	Coverage Δ
plugins/c8y_remote_access_plugin/src/proxy.rs	32.0% <0.0%> (+0.8%)	⬆️
plugins/c8y_remote_access_plugin/src/auth.rs	0.0% <0.0%> (ø)
plugins/c8y_remote_access_plugin/src/lib.rs	24.0% <0.0%> (+2.2%)	⬆️

... and 8 files with indirect coverage changes

[reubenmiller]

I've pushed some system tests, but don't be surprised if there are a few failures as the remote access has a few dependencies (e.g. generate ssh keypair, install go-c8y-cli, calling go-c8y-cli to create the passthrough configuration, and then run the ssh command).

[gligorisaev]

The added Test Step is OK, however having in mind that this test has additional test steps comming from #3007 I will do the more detail check in that PR

[reubenmiller]

The added Test Step is OK, however having in mind that this test has additional test steps coming from #3007 I will do the more detail check in that PR

Though we can't yet test the independence of the connection as a socket activated service is required for this (which is provided in #3007)

[Bravo555]

I'm not very familiar with the OG commit that's being reverted, but I don't see anything wrong.

[gligorisaev]

LGTM