bootstrap: allow deploying to remote rnodes

[Bill-Kunj]

In order to deploy to testnet, mainnet, rhobot, wherever, the scripts should accept an environment variable/switch/something. Scripts that should do nothing (like bootstrap/genesis) should fail gracefully when the environment variable is set to something other than localhost.
This also means auto-updating the URI files (MasterURI..json) we use to identify the master directory in the dev interface.

[ ] bootstrap
[ ] deploy
[ ] deploy-all
[ ] redeploy-class
[ ] create-snapshot
[ ] restore-snapshot
[ ] check-rnode
[ ] explore
[ ] eval
[ ] list-snapshot
[ ] lookupURI
[ ] propose
[ ] run-rnode
[ ] stop-rnode

[Bill-Kunj]

Too big for the rv2021 milestone, although it is related to #32 .