[ADD] iap_crm: bridge module for IAP and CRM

PURPOSE

Clean and improve IAP services integration in Odoo. Clean IAP integrations
tools and improve data sharing with base modules, notably for CRM and Partner.

SPECIFICATIONS

In this commit we create a bridge module between iap_mail and crm to hold
notably some fields used in various CRM integrations.

Now that we have clean bridge module we can safely update crm and partner
integrations dependencies.

LINKS

Task ID-2248367
Community PR odoo/odoo#53214
Enterprise PR odoo/enterprise#11258
Upgrade PR odoo/upgrade#1363
IAP PR odoo/iap-apps#191