Modified Authentication wrt new Users Table

Description

Login, Register and Forgot password Functionality now supports new Users Table Schema.

Type of PR

This PR is an improvement.

Technicalities

1. last_login_at updates at login.
2. created_at is set when user Registers.
3. modified_at updates when Users details are updated. (for now when new password set using forgot password)

Tests

Verify if last_login_at, created_at, modified_at is updated properly.

Try to break the code. (Challenge 😏 )

PS: This PR is not written from scratch. Changes are made based on the requirement.

Checklist:

• My pull request has a descriptive title (not a vague title like "Update index.md").
• My pull request targets the phoenix/develop branch of the repository.
• My commit messages follow best practices.
• My code follows the established code style of the repository.
• I added tests for the changes I made (if applicable).
• I added or updated documentation (if applicable).
• I tried running the project locally and verified that there are no visible errors.