Make CheckLink task cacheable

### Context

`CheckLink` tasks are expensive, can we make it cacheable, for example, make the date as input, so the same doc won't be checked in the same day?

Start at the CheckLink task and its build configuration, then trace how task inputs and caching are currently defined. Make the check's date an input so repeated runs for the same documentation on one day can reuse the result, and verify that a later date causes the task to run again.

Written by the indexing model from the issue text.