Use new hubspot_api version and try to sync contacts individually if a batched sync chunk fails

[mbertrand]

Pre-Flight checklist

• Testing
  • Code is tested
  • Changes have been manually tested

What's this PR do?

• Uses the new version of mitol.hubspot_api which can handle conflicts caused by a Hubspot contact having 2 emails associated with different bootcamps users
• Modifies the batch create/update tasks to try syncing contacts individually (to hit code above) if any API exceptions occur when running batch sync operations.

How should this be manually tested?

• Ask for access to the xprodev sandbox account for hubspot if you don't already have it.
• Copy the HUBSPOT_* settings values from RC to your .env file

Part 1:

• Create a new user in xpro, something like fake_user+1@gmail.com
• Find the contact in hubspot (may take a minute or so to show up) and add a secondary email to that contact: fake_user+2@gmail.com

• Register another new user with that same email - fake_user+2@gmail.com
• Check back on hubspot, that secondary email should be gone from the contact, and there should be a new contact with email fake_user+2@gmail.com

Part 2:

• Comment out your hubspot .env settings and restart your containers
• Create another new user, fake_user+3@gmail.com
• In hubspot, add that email to one of the existing contacts as a secondary email
• Uncomment your hubspot .env settings and restart your containers
• Run manage.py sync_db_to_hubspot --users create. It should complete successfully
• Check hubspot again, the secondary email from the contact should be gone and assigned to a new contact.

[arslanashraf7]

👍 Looks good, Also tested the PR and it works great.