Implement approval for TA training

Description

• Add a TA Training Approval Page (Similar to Raise Requests)
• A student can make a request to have their TA training approved and someone who can approve TA Training can approve or reject their request
• Strongly based on Raise Requests

Related Issues

• Resolves #44 (closed)

Checklist

• I have added a changelog entry to reflect the significant changes I made.