Fix bellows CLI

[puddly]

I've removed network backup and restore from the bellows CLI. It is too complex to maintain and should be kept in zigpy-cli.

The rest of the tools were spot checked and run.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 99.16%. Comparing base (93c671b) to head (a8566fb).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## dev #637 +/- ## ======================================= Coverage 99.16% 99.16% ======================================= Files 50 50 Lines 3459 3459 ======================================= Hits 3430 3430 Misses 29 29 ```

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[puddly]

In the future, we need to remove the bellows CLI entirely. This has a few blockers:

• Add the --i-understand-... flag to zigpy-cli, maybe call it --burn?
• Implement radio-agnostic sniffing.
• Add more options for network formation (forcing a PAN ID, EPID, channel, key, IEEE address, and so on).
• Maybe add a way to send ZCL commands to devices?