Add ignore transaction util

[tuchfarber]

Description:

Adds an ignore_transaction utility method. This will allows consuming apps to ignore transaction in views we don't want monitored (like /health/ checks)

JIRA:

No JIRA ticket.

Dependencies:

N/A

Merge deadline:

N/A

Installation instructions:

N/A

Testing instructions:

N/A

Reviewers:

• [ ] @edx/arch-review (Required)
• [ ] tag reviewer

Merge checklist:

• [ ] All reviewers approved
• [ ] CI build is green
• [x] Version bumped
• [x] Changelog record added
• [x] Documentation updated (not only docstrings)
• [x] Commits are squashed
• [ ] PR author is listed in AUTHORS

Post merge:

• [ ] Create a tag
• [ ] Check new version is pushed to PyPi after tag-triggered build is finished.
• [ ] Delete working branch (if not needed anymore)

Author concerns:

List any concerns about this PR - inelegant solutions, hacks, quick-and-dirty implementations, concerns about migrations, etc.

[robrap]

I’ll merge tomorrow if codecov doesn’t respond.

[robrap]

FYI: codecov/project never reported back, but codecov/patch succeeded, so I am merging.