feat: saas v2 in-desk checkout

[tanmoysrt]

If site is on trial, the banner will be -

If site is already on paid plan, in the menu bar there will be a button -

---

On clicking Subscribe or Manage , user will be redirected to a page for Integrated billing & checkout support.

For users, who is still on trial plan and haven't confirmed payment mode

For user, who has upgraded to a paid plan and have valid payment method, will be able to manage billing configuration and invoices

---

Some more screenshots of billing

---

A small frappe app has been written, which need to be installed with saas sites app. This will help in

• Showing the subscription banner based on current plan of site and team's onboarding details
• generate the short-lived access token to load the frappe cloud in-desk checkout page securely
• Also, this app allows to perform this action, If the logged-in user in the site is a System Manager.

Source code - https://github.com/frappe/fc_saas_helper

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 5.97015% with 126 lines in your changes missing coverage. Please review.

Project coverage is 37.40%. Comparing base (a995116) to head (18f9570). Report is 181 commits behind head on master.

Files with missing lines	Patch %	Lines
press/saas/api/billing.py	0.00%	58 Missing :warning:
press/saas/api/__init__.py	0.00%	33 Missing :warning:
press/saas/api/site.py	0.00%	14 Missing :warning:
press/saas/api/team.py	0.00%	9 Missing :warning:
press/saas/api/auth.py	0.00%	6 Missing :warning:
...aas/doctype/site_access_token/site_access_token.py	57.14%	6 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #2081 +/- ## ========================================== + Coverage 36.85% 37.40% +0.55% ========================================== Files 344 352 +8 Lines 28629 29276 +647 ========================================== + Hits 10551 10952 +401 - Misses 18078 18324 +246 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[nextchamp-saqib]

Instead of the dialog, maybe a separate "page" in the new app will look better?

[tanmoysrt]

Instead of the dialog, maybe a separate "page" in the new app will look better?

Yes, new page will be better ig. I will tryout tomorrow.