Remove legacy contact fields from provider model

[ryanmerolle]

NetBox version

v3.2.0

Feature type

Change to existing functionality

Proposed functionality

Remove legacy contact fields from provider model:

• Customer Portal
• NOC Contact
• Admin Contact

Use case

Currently there is the above contact text fields and a contact association field.

Database changes

Requires a migration to remove the contact fields from providers.

External dependencies

No response

[jeremystretch]

Blocked by #8234

[jeremystretch]

Disregard; #8234 has already been addressed.