Another config option on my quest to a `*_path` variant for every
secret. This time it’s `macaroon_secret_key_path`.
Reading secrets from files has the security advantage of separating the secrets from the config. It also simplifies secrets management in Kubernetes. Also useful to NixOS users.
During the migration the automated script to update the copyright
headers accidentally got rid of some of the existing copyright lines.
Reinstate them.
`synapse.config.__main__` has the possibility to read a config item. This can be used to conveniently also validate the config is valid before trying to start Synapse.
The "read" command broke in https://github.com/matrix-org/synapse/pull/10916 as it now requires passing in "server.server_name" for example.
Also made the read command optional so one can just call this with just the confirm file reference and get a "Config parses OK" if things are ok.
Signed-off-by: Jason Robinson <jasonr@matrix.org>
Co-authored-by: Brendan Abolivier <babolivier@matrix.org>
