[IMP] gmail: remove the enrichment feature from the addon

[std-odoo]

Purpose

Then enrichment feature of the addon made it slow and hard to use in practice, so we simplify it, and we keep only the core feature, which is logging the email on the records and viewing information about the contact.

If a conversation contains many contacts, before it took the first one. We can now choose the contact we want to open.

Allow searching any records, not only partners.

We fixed some UI issues than were introduced by update of the Gmail API.

Task-4727609