Add support for hooks during polling loop or at poller end #4614
Description
Describe the bug
Cacti has a feature called "remote_collect". However, that feature wan not differentiate between a hook that should function in the main poller loop and something that should execute at the poller bottom. As a result, a remote plugin that wishes to run remotely, has not way to either run in the main loop or at the end of processing.
For example, thold always needs to run in the main loop, but should not run at poller bottom. Other plugin may wish to not run in the main loop, but instead run on the poller bottom.
Expected behavior
Allow plugins to to define how they should run remotely more clearly.