Restrict project creation to org owners and org managers

### Problem Statement

An enterprise customer has requested the ability to restrict the permissions to create new projects to just org owners and org managers. Right now, org owners, org managers, and team admins have the ability to create new projects.

For large organizations, this can be problematic since a team admin can create a new project for their team and use up a lot of quota, without notifying or getting approval from their company's "Sentry administrators".

Currently the only setting available is to enable/disable project creation for members.

### Solution Brainstorm

A setting to enable/disable project creation for team admins. This would be extending the current org setting that enables/disable members to create new projects

### Product Area

Projects - Project Creation

Start by locating the existing organization setting and permission checks that control member project creation. Trace how team admins are authorized to create projects, then verify that the completed change blocks team admins while preserving creation for organization owners and managers, with tests covering those roles.

Written by the indexing model from the issue text.