Merge BigCommerce code into Nutmeg release

[becdavid]

• Merge in feat(bigcommerce_app) Merge in prior release changes. #153
• Merge in fix(bigcommerce): Update course enrollment check to include len. #162
• Merge in fix(third-party-auth): Need to account for additional required demographic fields for BigCommerce provider. #179
• Merge in fix(third-party-auth): Need to account for additional required demographic fields for BigCommerce provider for maple release. #180