- tweaked resources and containers to accelerate tests

MockBlockchain:
- Implemented mock-blockchain module to facilitate testing and debugging of DLT connector & workflows
- Added manifests, Dockerfile, etc.

DLT Connector:
- corrected requirements.in
- updated Dockerfile
- WIP: implementation of test_unitary.py

DLT Gateway:
- Improved/extended Dockerfile
- Moved Dockerfile to correct folder
- Corrected import path for proto files

Context service:
- corrected port numbers

Device service:
- corrected port numbers
- upgraded gitlab-ci configuration

Preliminary unfinished version of device service and Context API based on Redis. To be finished, it is just a backup.

This reverts merge request !3