[CHIA-435] Add chia wallet signer commands

[Quexington]

This PR caps off a thread of work that supports external signers for transactions generated by the wallet. With these commands, it should be possible to run two wallets with different security qualities and transport transactions back and forth between them for the colder one to sign. It currently uses binary files/QR codes to accomplish this although other methods of transport are certainly on the table.

[github-actions]

File	Coverage	Missing Lines
chia/wallet/wallet_state_manager.py	75.0%	lines 400, 402

Total	Missing	Coverage
303 lines	2 lines	99%

[coveralls-official]

Pull Request Test Coverage Report for Build 9389919648

Details

• 299 of 301 (99.34%) changed or added relevant lines in 6 files are covered.
• 17 unchanged lines in 7 files lost coverage.
• Overall coverage increased (+0.02%) to 90.945%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
chia/wallet/wallet_state_manager.py	6	8	75.0%

Files with Coverage Reduction	New Missed Lines	%
chia/server/node_discovery.py	1	79.96%
chia/daemon/client.py	1	73.94%
chia/daemon/server.py	1	83.24%
chia/full_node/full_node_api.py	2	81.0%
chia/_tests/core/util/test_lockfile.py	2	90.28%
chia/rpc/rpc_server.py	3	88.04%
chia/wallet/wallet_node.py	7	88.25%

Totals
Change from base Build 9389912469:	0.02%
Covered Lines:	100691
Relevant Lines:	110666

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💛 - Coveralls

[wjblanke]

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