fix: don't freeze dev dependencies, include nested deps with extra markers

[ajkerrigan]

Looks like when this plugin checks path deps, it's looking at the dev group by default and bringing extras (and their dep trees) into the frozen wheel.

Summary of the changes:

• Only freeze deps from the main group (don't freeze dev dependencies).
• Freeze the full nested dependency tree.
• Include extra markers in the frozen Requires-Dist: lines for dependencies that come in via extras. So...
  • This test app depends on pytest-cov, which depends on coverage, which includes tomli as part of the toml extra. When we freeze the tomli dependency, don't include an extra marker.
  • c7n-mailer includes c7n-gcp as part of the gcp extra. Do freeze c7n-gcp with the ... and extra == "gcp" marker.
  • c7n-mailer includes several nested cloud provider-specific dependencies that come in via gcp or azure markers. Add extra markers for those.

This change effectively looks to mirror the utility of requirements.txt files created with poetry export, but specifies extras at install time rather than build time. For example:

# Export Flow (without extras)
poetry export -f requirements.txt > requirements.txt && pip install -r requirements.txt
# Freeze-wheel Flow
poetry build && poetry freeze-wheel && pip install my_frozen_wheel

# Export Flow (with extras)
poetry export --extras gcp -f requirements.txt && pip install -r requirements.txt
# Freeze-wheel Flow
poetry build && poetry freeze-wheel && pip install my_frozen_wheel[gcp]

Addresses https://github.com/cloud-custodian/cloud-custodian/issues/8488

[codecov[bot]]

Codecov Report

Patch coverage: 100.00% and project coverage change: +2.86 :tada:

Comparison is base (b6ebff8) 87.73% compared to head (5287e23) 90.59%.

:exclamation: Current head 5287e23 differs from pull request most recent head 3092d9c. Consider uploading reports for the commit 3092d9c to get more accurate results

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #11 +/- ## ========================================== + Coverage 87.73% 90.59% +2.86% ========================================== Files 1 1 Lines 163 202 +39 ========================================== + Hits 143 183 +40 + Misses 20 19 -1 ``` | [Impacted Files](https://app.codecov.io/gh/cloud-custodian/poetry-plugin-freeze/pull/11?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cloud-custodian) | Coverage Δ | | |---|---|---| | [src/poetry\_plugin\_freeze/app.py](https://app.codecov.io/gh/cloud-custodian/poetry-plugin-freeze/pull/11?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cloud-custodian#diff-c3JjL3BvZXRyeV9wbHVnaW5fZnJlZXplL2FwcC5weQ==) | `90.59% <100.00%> (+2.86%)` | :arrow_up: |

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