S3 Improvements (#642)

* S3 improvements.

* Disable failing unit tests.

* Improve stability.

* Add model uuid check.

* Improvements for async replication.

* Revert "Disable failing unit tests."

This reverts commit f13b146.

* Fix s3 upload and s3 read functions. Improve check_stanza and initialize_stanza exceptions.

* Improve responsiveness of is_pitr_failed.

* Unit tests.

* Format.

* Improve async replication tls stability.

Author: Zvirovyi