Rewrite command parsing/serialization

[puddly]

This PR addresses a few code quality issues with the radio library:

• The payload length is computed by hand for each frame that requires it.
• Parameter names are missing for both requests and responses.
• Device states aren't logged accurately.
• The "free slots" flag is ignored.
• Sequence numbers alone aren't enough to match responses to requests and results in spurious bad request/response matching.

Unit tests are broken but backup, restore, permit, and energy-scan all work on a real Conbee II.

[codecov[bot]]

Codecov Report

Attention: 4 lines in your changes are missing coverage. Please review.

Comparison is base (3c82aed) 97.95% compared to head (a14912d) 98.76%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## dev #231 +/- ## ========================================== + Coverage 97.95% 98.76% +0.81% ========================================== Files 6 7 +1 Lines 1025 894 -131 ========================================== - Hits 1004 883 -121 + Misses 21 11 -10 ``` | [Files](https://app.codecov.io/gh/zigpy/zigpy-deconz/pull/231?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=zigpy) | Coverage Δ | | |---|---|---| | [zigpy\_deconz/types.py](https://app.codecov.io/gh/zigpy/zigpy-deconz/pull/231?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=zigpy#diff-emlncHlfZGVjb256L3R5cGVzLnB5) | `100.00% <100.00%> (ø)` | | | [zigpy\_deconz/uart.py](https://app.codecov.io/gh/zigpy/zigpy-deconz/pull/231?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=zigpy#diff-emlncHlfZGVjb256L3VhcnQucHk=) | `100.00% <100.00%> (ø)` | | | [zigpy\_deconz/utils.py](https://app.codecov.io/gh/zigpy/zigpy-deconz/pull/231?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=zigpy#diff-emlncHlfZGVjb256L3V0aWxzLnB5) | `100.00% <100.00%> (ø)` | | | [zigpy\_deconz/api.py](https://app.codecov.io/gh/zigpy/zigpy-deconz/pull/231?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=zigpy#diff-emlncHlfZGVjb256L2FwaS5weQ==) | `98.73% <99.45%> (+3.44%)` | :arrow_up: | | [zigpy\_deconz/zigbee/application.py](https://app.codecov.io/gh/zigpy/zigpy-deconz/pull/231?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=zigpy#diff-emlncHlfZGVjb256L3ppZ2JlZS9hcHBsaWNhdGlvbi5weQ==) | `97.86% <89.28%> (-0.61%)` | :arrow_down: |

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