Reckless: add rust installer and json output

[endothermicdev]

This PR does several things:

1. Adds an installer for rust plugins.
2. Adds a --version flag.
3. Refactors logging and output.
4. Allows option flags in any order. (previously limited to before subcommands only)
5. Adds a --json output option.

In general, this prepares for a reckless-rpc plugin coming next.

[ShahanaFarooqui]

• Search without result does not show any message, for example: reckless search nonexistingplugin should show a message stating that plugin not found/plugin nonexistingplugin not found

• holdinvoice install command throws below error (reckless --regtest --verbose --json install holdinvoice)

Traceback (most recent call last):
  File "/usr/local/bin/reckless", line 1803, in <module>
    log.add_result(args.func(target))
  File "/usr/local/bin/reckless", line 1314, in install
    installed = _install_plugin(src)
  File "/usr/local/bin/reckless", line 1245, in _install_plugin
    staged_src = INSTALLER.dependency_call(staged_src)
  File "/usr/local/bin/reckless", line 936, in cargo_installation
    log.error(cargo.stderr.read())
AttributeError: 'str' object has no attribute 'read'

• Can reckless install accept plugin options too, like summars-columns, summars-sort-by with reckless install summars?

[endothermicdev]

Search without result does not show any message

Good catch, I changed the default logging level and missed changing this one to logging.info fixed!

holdinvoice install command throws below error

Ah, right, I changed the call from Popen to run, which has the outputs strings. Also raised the right error to catch here.

[endothermicdev]

Can reckless install accept plugin options too, like summars-columns, summars-sort-by with reckless install summars?

I like this idea. We could pass these in a list to an optional keyword, and then maybe track the options in the metadata. Is there a good way to validate the plugins options though? Any errors will cause the node to not start.

[rustyrussell]

Ack 87895bd