* use tls for nats connections
* add config options for nats client tls config
* add nats tls config to CI
* add function to create a certpool
* add option to provide a rootCA to validate the server's TLS certificate
* add option to provide a rootCA to validate the server's TLS certificate
* add option to provide a rootCA to validate the server's TLS certificate
* add option to provide a rootCA to validate the server's TLS certificate
* configure nats clients in reva to use tls
Use OCIS_URL as the link base. This change also makes sure that the
top-level OcisURL config value gets a default assigned, even when
OCIS_URL is unset.
Fixes: #4688
The help flag is configured automatically by default already. We don't
need to redo that for every single service.
This also addresses one of the finding of "go race" (#4088)