Issue:
refactor: deprecate V1 signin, verify email and invite APIs

Currently the following endpoints are not being used by the dashboard
`/user/signin`
`/user/verify_email`
`/user/invite`

New APIs are created for the above APIs which are
`/user/v2/signin`
`/user/v2/verify_email`
`/user/invite_multiple`

The old APIs are kept for backwards compatibility, as the movement is completed entirely from the FE side as well, old APIs can be removed.

Resolution:
<think>
PR Context:
- Title: refactor(user): Deprecate Signin, Verify email and Invite v1 APIs
- Merged: 2024-04-30T10:12:31Z
- Files changed: 7 files
- Commits: 4 commits

Implementation approach:
## Type of Change
<!-- Put an `x` in the boxes that apply -->

- [ ] Bugfix
- [ ] New feature
- [ ] Enhancement
- [x] Refactoring
- [ ] Dependency updates
- [ ] Documentation
- [ ] CI/CD

## Description
<!-- Describe your changes in detail -->
This PR will remove the following endpoints and corresponding APIs
`/user/signin`
`/user/verify_email`
`/user/invite`

### Additional Changes

- [x] This PR modifies the API contract
- [ ] This PR modifies the database schema
- [ ] Th
</think>

To implement this, you'll need to modify:


**Detailed Implementation:**


**Commit 1:** refactor(user): Deprecate Signin, Verify email and Invite v1 APIs (#4465)
Files to modify:


**crates/api_models/src/events/user.rs**
  Modify existing code

**crates/api_models/src/user.rs**
  Remove:
    - struct: pub::InviteUserResponse

**crates/router/src/core/user.rs**
  Remove:
    - function: pub::signin_without_invite_checks
    - function: pub::invite_user
    - function: pub::verify_email_without_invite_checks

**crates/router/src/routes/app.rs**
  Modify existing code

**crates/router/src/routes/lock_utils.rs**
  Modify existing code

**crates/router/src/routes/user.rs**
  Remove:
    - function: pub::user_signin_without_invite_checks
    - function: pub::invite_user
    - function: pub::verify_email_without_invite_checks

**crates/router_env/src/logger/types.rs**
  Modify existing code