cmd/connect: establish a TLS connection

[adamdecaf]

It seems handy to have a connect <url> subcommand which can take in a list of certificates (i.e. -file, -app) and use those for a connection to <url>.

When we start wanting to create certificate stores on the fly it would be nice to help verify connections work.

# Trim down a java truststore
$ cert-manage whitelist -app java -file ./cacerts -whitelist wh.json

# Verify connections work
$ cert-manage connect -file ./cacerts https://example.com 

[adamdecaf]

Can we specify multiple hosts?