Similar to #14274, we require further insight into how long each script takes to execute in the agent.

Scripts can run:

• on startup
  • can optionally have a flag (start_blocks_login) which prevents users logging in until script exits
• on stop
• on a cron schedule

We ultimately want to be able to indicate how long a workspace took to become "ready" from the time the build was initiated all the way to the agent scripts with blocking behaviour exiting. Scripts which do not block (i.e. run on startup without start_blocks_login, on stop, or on a cron schedule) should also be tracked and have some indication that they are non-blocking.

We need to track when each script started, exited, and with what status.