[IMP] hr_holidays: add accrual allocations support

We need to support the accrual allocation for leaves.
This is a special type of allocations that adds some leaves to the
allocation every X amount of time worked.

This kind of allocations is especially used in the USA, but can also be
used in other contexts (eg: In Belgium we could allocate 20 days per
year for the legal leaves)

These allocations have support for :

  * A max balance limit
  * Going in negative (if set on the leave_type and the manager
    approves the leaves)
  * Removing the unpaid leaves from the quantity of days worked
  * Setting an end date after which it does not allocate anymore leaves

Task #46114
Closes #22292