Recurrence rules BY* validations

[allenporter]

Is your feature request related to a problem? Please describe.
Need to enforce constraints on the BY* fields for recurrence rules.

Describe the solution you'd like
Add pydantic validations to enforce the #s used (e.g. month is between 1 and 12, day of month is between 1 and 31, etc)

[allenporter]

Another example:

• The BYDAY rule part MUST NOT be specified with a numeric value when the FREQ rule part is not set to MONTHLY or YEARLY. Furthermore, the BYDAY rule part MUST NOT be specified with a numeric value with the FREQ rule part set to YEARLY when the BYWEEKNO rule part is specified.