Added support for the bulk create traces endpoint

[impolitepanda]

Proposed changes

• added support for the bulk create traces endpoint
• fixed usage of utcnow which is deprecated and flagged for removal

Related issues

• Performance improvement: bulk insert expectation traces and results openaev#2873

Checklist

• I consider the submitted work as finished
• I tested the code for its functionality
• I wrote test cases for the relevant uses case
• I added/update the relevant documentation (either on github or on notion)
• Where necessary I refactored code to improve the overall quality
• For bug fix -> I implemented a test that covers the bug