refactor(backend): spinoff volumes

Base in frontend actions slightly improved. Need some work though

issue #852

Added Kali 2020 to the default ISO list

Properly reads the png blob

fix(renewMac): Renew MAC on more than 1 NIC

closes issue #1201

This problem raised when creating multiple clones
and starting them all at once.

* fix(frontend): copy screenshot updated to db

necessary because of @eskumon changes

closes issue #1221

Instead of searching for machines in nodes we keep
track of instances so it is faster to remove them.

issue #1235

feature(volumes): rebase volume files

feture(frontend):  allow machines if access by client granted

* feature(frontend): setup access by client
* test(frontend): test ws with access grant
* feature(access): allow by accept-whatever with many options
* test(frontend): check access by encoding

issue #1213

* list machines
* list bases user

* fix(frontend): copy contents so it flickrs less

issue #1228

issue #1228

fix(backend): remove temporary user on shutdown or remove

* test(backend): temporary user get removed
* test(auth): check when upgrade
* refactor(frontend): allow ws anonyous on some channels
* refactor(frontend): removed legacy ping backend
* test(volatile): check users are removed

closes issue #1023

refactor(frontend): ping backend WS

issue #1196

* test(backend): check drivers are kept on migration

Positive duplication of problem reported by @eagliardi

issue #1135

fix(backend): only wait for pids on processing reqs