Geo: For QA tests, disable writing SSH keys to disk

Problem

When running QA tests for Geo, there's an inconsistency between verifying SSH keys on the primary vs. the secondary. By default, Write to "authorized_keys" file is enabled, which means when an SSH key is created on the primary (which keys are as part of the QA tests), the SSH key is inserted into the DB and written to disk - ~git/.ssh/authorized_keys. The secondary then replicates the SSH key in the DB but it does not replicate the SSH key that's in ~git/.ssh/authorized_keys on the primary.

This leads to an inconsistency in verifying SSH keys that can (and did) lead to confusion.

Proposal

Disable writing SSH keys to disk via /admin/application_settings/network - 'Performance optimization' >