fix(Billing): update app limits to remove free contributors

[mikewuu]

Now that the Free plan < 3 contributors has been removed, we need to update the in-app limits.

• [ ] remove < 3 contributor check. Always require plan
• [ ] Introduce plan-level features
• [ ] Introduce pay-wall for pages
• [ ] Update free trial period to 3 months
• [ ] Make sure free trial cannot be extended

[homie-gg[bot]]

Here are some pull requests that might be helpful reference for this task:

• feat(Billing): add per-seat billing
• fix(Billing): update plan cards to use new plans