Addresses:

- DOC-11203
- DOC-11048
- DOC-11049

Summary of changes:

- Update 'Licensing FAQs' with the following:

  - Information about the new licensing tiers

  - Instructions for self-serve Enterprise Trial and Enterprise Free
    licenses in Cloud Console

  - Updated information about how to monitor for license expiry in DB
    Console (with a link to updated UI docs that include the exact
    messages)

  - A description of what throttling is and how it works

  - A note that single-node developer clusters do not require a license
    key

- Update 'DB Console Overview > License expiration message' with the
  specific messages that may be emitted by Console depending on the
  status of the cluster's license