fix(mqtt): Map mosquitto bridge service health status updates

[albinsuresh]

Proposed changes

• [x] Map health status updates from mosquitto bridge services
• [x] Avoid redundant service creation messages while mapping the health status updates
• [x] Ensure that the initial health status is propagated as-is without assuming it to be up

Types of changes

• [x] 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

https://github.com/thin-edge/thin-edge.io/issues/2902

Checklist

• [x] I have read the CONTRIBUTING doc
• [x] I have signed the CLA (in all commits with git commit -s)
• [x] I ran cargo fmt as mentioned in CODING_GUIDELINES
• [x] 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

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 94.28571% with 2 lines in your changes are missing coverage. Please review.

Project coverage is 78.0%. Comparing base (8a91efb) to head (d52bbdf). Report is 2 commits behind head on main.

Additional details and impacted files

| [Files](https://app.codecov.io/gh/thin-edge/thin-edge.io/pull/2903?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=thin-edge) | Coverage Δ | | |---|---|---| | [crates/core/tedge\_api/src/health.rs](https://app.codecov.io/gh/thin-edge/thin-edge.io/pull/2903?src=pr&el=tree&filepath=crates%2Fcore%2Ftedge_api%2Fsrc%2Fhealth.rs&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=thin-edge#diff-Y3JhdGVzL2NvcmUvdGVkZ2VfYXBpL3NyYy9oZWFsdGgucnM=) | `92.6% <ø> (ø)` | | | [crates/core/tedge\_api/src/mqtt\_topics.rs](https://app.codecov.io/gh/thin-edge/thin-edge.io/pull/2903?src=pr&el=tree&filepath=crates%2Fcore%2Ftedge_api%2Fsrc%2Fmqtt_topics.rs&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=thin-edge#diff-Y3JhdGVzL2NvcmUvdGVkZ2VfYXBpL3NyYy9tcXR0X3RvcGljcy5ycw==) | `86.9% <100.0%> (-0.6%)` | :arrow_down: | | [...s/extensions/c8y\_mapper\_ext/src/service\_monitor.rs](https://app.codecov.io/gh/thin-edge/thin-edge.io/pull/2903?src=pr&el=tree&filepath=crates%2Fextensions%2Fc8y_mapper_ext%2Fsrc%2Fservice_monitor.rs&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=thin-edge#diff-Y3JhdGVzL2V4dGVuc2lvbnMvYzh5X21hcHBlcl9leHQvc3JjL3NlcnZpY2VfbW9uaXRvci5ycw==) | `97.6% <100.0%> (+1.2%)` | :arrow_up: | | [crates/extensions/c8y\_mapper\_ext/src/converter.rs](https://app.codecov.io/gh/thin-edge/thin-edge.io/pull/2903?src=pr&el=tree&filepath=crates%2Fextensions%2Fc8y_mapper_ext%2Fsrc%2Fconverter.rs&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=thin-edge#diff-Y3JhdGVzL2V4dGVuc2lvbnMvYzh5X21hcHBlcl9leHQvc3JjL2NvbnZlcnRlci5ycw==) | `83.6% <77.7%> (+<0.1%)` | :arrow_up: | ... and [1 file with indirect coverage changes](https://app.codecov.io/gh/thin-edge/thin-edge.io/pull/2903/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=thin-edge)

[github-actions[bot]]

Robot Results

:white_check_mark: Passed	:x: Failed	:next_track_button: Skipped	Total	Pass %	:stopwatch: Duration
443	0	3	443	100	1h0m32.488258999s

[albinsuresh]

However, the code related to health status is still fragile because unstructured.

• There are two similar HealthStatus structs defined by c8y related crates (c8y_api and c8y_mapper_ext).
• The respective roles of tedge_api and c8y_api is not clear. Several methods should be moved into tedge_api to encapsulate all the tedge conventions.
• This PR introduces UP_STATUS and DOWN_STATUS constants, but "up" and "down" literals are used everywhere.

I completely agree and this was the cleanup that I wanted to do as well. But, kept the minimal changes in this PR because of the urgency in fixing the bug. Will definitely do a follow-up PR with all that cleanup.