This reverts commit 363c3214.

Also made garbage collection faster.

Added logging in case of exception in GC.
Fixed wrong GC handler behaviour when subprocess exits/crashes.

Also removed the heartbeat from the GC's main functions (it is now handled in a separate thread).

Added missing destructor for GCHandler.
Added subprocess to taped's process manager.

Created a garbage collector subprocess for the drive daemon.
Created a AgentHeartbeat thread and added it to frontend, drive subprocess and GC subprocess.
Fixed logs and drive subprocess.
Renamed common/threading/Threading.[hc]pp to Thread.[hc]pp as there is only one class left in this file.

...when it only contains orphaned references.

(It happens later).

Moved mhvtl installation and fixed its repo dependency.
Minor fixes for environement recreation.

... added missing file.

Fixed home directory not readable (prevented the frontend from running).
Added installation of CASTOR's rmcd to the image.

Fixed missing dependencies in image.

Fixed directory name in docker which did not match the top one.
Split the image create to allow fast script fixing.

Also moved image build out of vmBootstap directory.