Display authorization settings to UIS owner?

[hjoliver]

See also #259

Authorization config requires valid Python syntax as well as the correct data structure and item names and values. Any error results in the user config being silently ignored. (Accessing user permissions are logged, if logging with sufficient verbosity, to the hub console, but that ain't much use).

We should probably display a table of authorization settings in the UI, for the authenticated UIS owner to see, and encourage users to double check that after making any changes.

[hjoliver]

Note the Authorized Operations User Profile div in @datamel's cylc/cylc-ui#728 goes some way toward this, in that dashboard (and user profile) are relative to the target, not authenticated, user.

[oliver-sanders]

We have some minimal validation for the site-config -

cylc-uiserver/cylc/uiserver/app.py

Lines 316 to 322 in 4373c0c

	@validate('site_authorization')
	def _check_site_auth_dict_correct_format(self, proposed):
	# TODO: More advanced auth dict validating
	if isinstance(proposed['value'], dict):
	return proposed['value']
	raise TraitError(
	f'Error in site authorization config: {proposed["value"]}')

This could be improved and expanded to the user config which could then fail for invalid configs.