Improve handling of Rendered Task Instance Fields

### Body

The current way how Rendered Task Instance Fields are handled (deleting old records and storing even big rendered task instance fields in the table) introduce a number of problems:

* Deadlocks on MySQL only
* https://github.com/apache/airflow/issues/32294
* https://github.com/apache/airflow/issues/29687
* https://github.com/apache/airflow/issues/18512

Those lead to workarounds such as #18616 and #32341

There are other reasons why big rendered fields should also be handled differently:

* https://github.com/apache/airflow/issues/28199

There was a discussion about deprecating it - that had never been concluded - but some good ideas and reasons why we can't **just** deprecate it have been explained there:

https://lists.apache.org/thread/jfzxq6xf8z5ss11hjl1yn41dd4mvk7cm

It would be great if someone picks up the discussion, lead it to conclusions and implement it.

### Committer

- [X] I acknowledge that I am a maintainer/committer of the Apache Airflow project.

Start by reviewing the linked deadlock and rendered-field issues, workarounds #18616 and #32341, and the Apache mailing-list discussion. Done means the discussion reaches a conclusion and the resulting implementation addresses deadlocks and the handling of large rendered task instance fields.

Written by the indexing model from the issue text.