Detect invalid entity (like `&nsbp;`)

[regseb]

Is your feature request related to a problem? Please describe.
Detect invalid entity (like &nsbp; or &IDoNotExist;).

Describe the solution you'd like
Add the entity-invalid rule which checks that the entities are valid.

Additional context

• Named character references: List of entities names that are supported by HTML.
• character-entities: npm package containing the entities.