Issue:
feat: Role information in list merchants API

- HCC FE is building a profile feature where they want to show all the merchants where the current user is part of.
- This also includes the role they were assigned in each merchant account.
- We have an API which lists merchant accounts but it doesn't send role they were assigned.
- So, we can change that API to also send the roles.

Resolution:
<think>
PR Context:
- Title: feat(users): Add role specific fields for list merchants API
- Merged: 2024-04-10T10:43:24Z
- Files changed: 7 files
- Commits: 7 commits

Implementation approach:
## Type of Change
<!-- Put an `x` in the boxes that apply -->

- [ ] Bugfix
- [ ] New feature
- [x] Enhancement
- [ ] Refactoring
- [ ] Dependency updates
- [ ] Documentation
- [ ] CI/CD

## Description
<!-- Describe your changes in detail -->
- This PR adds `role_id`, `role_name`, `org_id` fields in list merchants for user API.
- New route `/user/merchants/list` which points to the same function as `/user/switch/list`.
### Additional Changes

- [x] This PR modifies the API cont
</think>

To implement this, you'll need to modify:


**Detailed Implementation:**


**Commit 1:** feat(users): Add role specific fields for list merchants API (#4326)
Co-authored-by: hyperswitch-bot
Files to modify:


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

**crates/router/src/core/user.rs**
  Modify existing code

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

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

**crates/router/src/types/domain/user.rs**
  Modify existing code

**crates/router/src/utils/user.rs**
  Modify existing code

**crates/router/src/utils/user_role.rs**
  Add:
    - function: pub::get_multiple_role_info_for_user_roles