add option to configure polling interval

[pascal-sochacki]

Description of your changes

Add option to change the poll interval

I have:

• [x] Read and followed Crossplane's contribution process.
• [x] Run make reviewable to ensure this PR is ready for review.

[Duologic]

Can you rebase this (and hopefully trigger CI again)?

[pascal-sochacki]

Quite new to fork. Did I rebase correctly?