feat(demo-mode): passwordless login

[obostjancic]

• Closes: Automatically log vistors in #79007

Context

• In order to replace Current sandbox, which is a self-hosted instance available at https://try.sentry-demo.com/ we created a SaaS sandbox org https://sandbox.sentry.io/
• Event data in sandbox org will be synced with demo org through sentry-mirror
• In order to allow public access to this org we created a Demo User
  • that should have read-only access to only this org. PoC PR
  • that should be able to log in automatically. WIP PR
• sandbox org and Demo User are behind demo-mode.orgs and demo-mode.users options respectively. Those options are added in PR

[codecov]

Codecov Report

Attention: Patch coverage is 92.50000% with 3 lines in your changes missing coverage. Please review.

✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/sentry/web/frontend/auth_login.py	40.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #83090      +/-   ##
==========================================
+ Coverage   87.63%   87.68%   +0.05%     
==========================================
  Files        9492     9455      -37     
  Lines      541325   538413    -2912     
  Branches    21234    21006     -228     
==========================================
- Hits       474383   472123    -2260     
+ Misses      66594    65933     -661     
- Partials      348      357       +9     

[mdtro]

Can you add tests to ensure this all behaves as expected?

[obostjancic]

Can you add tests to ensure this all behaves as expected?

It should be all covered with tests now :D

[constantinius]

lgtm