Expose a list of restricted datasets and repos that have permission to access them

[iaindillingham]

It would be helpful to expose a list of restricted datasets in the docs, in a human-readable form. The canonical list is within opensafely/check.py. For example:

opensafely-cli/opensafely/check.py

Lines 25 to 31 in a25d148

	RestrictedDataset(
	name="icnarc",
	cohort_extractor_function_names=[
	"admitted_to_icu",
	],
	ehrql_table_names=[],
	),

It would also be helpful to expose a list of repos that have permission to access them. The canonical list is within repository_permissions.yaml. For example:

opensafely-cli/repository_permissions.yaml

Lines 1 to 2 in a25d148

	opensafely/risk-factors-research:
	allow: ['icnarc']

Helpful? How? Because the IG team receive a notification when a repo accesses a restricted dataset erroneously (opensafely-core/research-action#99). Putting a notification in context helped Juliet understand it, when we discussed it earlier today. However, she wanted to know more about which datasets were restricted and which repos had permission to access them.