Support backtick as identifier quote character

Problem/Motivation

Sometimes backtick is used as identifier quote character. In IntColumnHandler->create() it's assumed, that only double quotation mark can be used.

Steps to reproduce

Set up database with non-ACSI quote mode, install Drupal 10 with this module and create content with field of type, provided by module. Personally, I've faced this issue during migration from D9 to D10 and execution of `dynamic_entity_reference_update_8201` update function.

Proposed resolution

Modify code to assume, that backtick can be used as identifier quote character.

Remaining tasks

Review patch, feedback, commit.