Generated pelican Transport needs to be regenerated after configs

[bbockelm]

The transport can be changed as part of the configuration process. For example, it can:

1. Disable the TLS validation
2. Add a newly-generated CA to the configuration (see Origin self-test #167)

The way we do (1) currently is overwrite the TLS validation setting each time we get a pointer to the transport. That's not thread-safe -- and we don't want to recompute this each time.

Instead, move the GetTransport() to the configuration sub-module so we can lazily recreate the object each time the configuration (client or server) is run.