add reset password mechanism

[LeoQuote]

Description

Add a mechnism for user to reset password for themselves. The full steps are:

1. User request to reset password, only email address is needed
2. dify send user a password, containing a url with a token that expires.
3. user entering the page, input the new password, send them back to dify
4. dify verify the new password and token, change the password if all good.

• [ ] Frontend
• [ ] Init reset api
• [x] Finish reset api

I'm not sure if the team would accept pr like this, so first a very raw draft.

Type of Change

• [x] New feature (non-breaking change which adds functionality)

How Has This Been Tested?

• [ ] Not tested

Suggested Checklist:

• [ ] I have performed a self-review of my own code
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] My changes generate no new warnings
• [ ] I ran dev/reformat(backend) and cd web && npx lint-staged(frontend) to appease the lint gods
• [ ] optional I have made corresponding changes to the documentation
• [ ] optional I have added tests that prove my fix is effective or that my feature works
• [ ] optional New and existing unit tests pass locally with my changes