Backend changes to add User Job Title

What does this MR do?

This MR adds support for User Job title to be used in User Profile pages.

1. Adds a new column job_title in users table
2. Controller changes to permit and save job_title. UI related changes for this column to be added in !25155 (merged)
3. Ability to retrieve job_title through User apis
4. Updates api documentation

Test cases:

Workflow	Expected	Status
User updates job_title through Settings page	Stores job_title in db
User visits Settings page	Display job_title if present
User retrieve api: /api/v4/users/1	Return 'job_title' value as appropriate

Closes #207043 (closed)

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team