[wolf4ood]

What this PR changes/adds

• Tuning: the "State Machines" section gets new subsections:
  • Lease duration: the three lease-duration settings, their PT60S default, and how to size them.
  • Task-based state machine (NATS): the retry settings (no maximum delay), the provisioning of the streams and
    consumers in production (persistent storage, MaxAckPending, ack wait), and the SQL task store with several
    replicas.
  • A link to the new page.
• New page for-adopters/control-plane/state-machines: the accepted limitations of the poll-based and task-based
  state machines. Each one covers what happens, when, the impact, and the mitigation where there is one.

Why it does that

The hardening of the state machines (eclipse-edc/Connector#6105, eclipse-edc/Connector#6116) fixed most of the issues
found and accepted the others as "Informative". Several of these are operating guidance, so they are documented
instead of being kept only in closed issues. The page can be updated as items get fixed, e.g. head-of-line blocking
once the batch is processed by a pool of workers.

Further notes

List other areas of code that have changed but are not necessarily linked to the main feature. This could be method
signature changes, package declarations, bugs that were encountered and were fixed inline, etc.

Who will sponsor this feature?

Please @-mention the committer that will sponsor your feature.

Linked Issue(s)

Closes # <-- insert Issue number if one exists

Please be sure to take a look at the contributing guidelines and our etiquette for pull requests.