[FEATURE] Add a new resource to set individual permissions levels for token/password usage

[alexott]

Use-cases

Right now databricks_permissions is used to define all permissions for a given securable object, including a special objects "token usage" and "password usage" (doc) that exist as a single instance. Because all permissions needs to be defined inside the same resource, it's getting hard to use it, especially if people are trying to assign permissions inside the modules - in this case all previous assignments will be removed, leading to revoke of the tokens, etc. because we're using PUT API to set permissions

Proposal

This problem could be solved by adding a new resource that will use PATCH API to add/remove individual permissions, although it may lead to inability to detect a configuration drift if changes to permissions are made outside of the terraform.

[nkvuong]

This pops up a few times

• [FEATURE] Support databricks_grant, databricks_permission etc. resources #1976 also asks for this
• [ISSUE] Issue with databricks_permissions resource #2104 (comment) seems to have this issue