Change praxis to use tunnel rmi over ssh, instead of rmi over http

HTTP proxying feature from RMI has been deprecated in JDK 8, and it is
completely removed in JDK 9.

New dependencies:

- sshjs, v0.24
  https://github.com/hierynomus/sshj
  https://mvnrepository.com/artifact/com.hierynomus/sshj

- Bouncy Castle Crypto package, v1.59
  https://mvnrepository.com/artifact/org.bouncycastle/bcprov-ext-jdk15on

- EdDSA Java v0.2.0
  https://mvnrepository.com/artifact/net.i2p.crypto/eddsa

- slf4j v1.7.7
  https://mvnrepository.com/artifact/org.slf4j/slf4j-api