Log a message when a hidden service delays new introduction point circuits

When a hidden service stops making new introduction point circuits, it would be useful to log a message saying:

• how many connections it has made so far,
• how long it took it to make those connections,
• what the connection limit is,
• in what time that many connections can be made, and
• a list of the current intro point connections.

This is a follow-up to legacy/trac#21599 (moved).