Lint

Remove `TimeoutManager` and add command for requesting messages for `P2PHandle` #70

Job	Run time
Check code spellings	7s
Run clippy on crates	1m 15s
Check that crates compile on their own	2m 0s
Check code formatting	25s
Lint Protocol Buffers	5s
Lint and check formatting of TOML files	3s
Check that lints passed	1s
	3m 56s

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