[Feature Request] generate config under /etc in a safe manner

[adaniline-rkt]

Is your feature request related to a problem? Please describe.

Security scanning tools, like Falco, report a vulnerability in Temporal containers for writing under the /etc folder:

Error File below /etc opened for writing (user=<NA> user_loginuid=-1 command=dockerize -template /etc/temporal/config/config_template.yaml:/etc/temporal/config/docker.yaml

Describe the solution you'd like

Generate the config file in an empty dir volume by an init container, and mount the volume under /etc/temporal in the service container

[robholland]

We'll be removing the need to write configs to the filesystem. See temporalio/temporal#6251 for context.