feat(ingest) - clean expired ingest content.

Refactored the ingest commands in separate files.
docker: added initial infrastructure
fix(docker): start_container script
fix(docker: start_container): hardcoded host ip
Merge pull request #234 from amagdas/clean-expired

feat(ingest) - clean expired ingest content.
fix(docker: start_container): forwared websockets' port
Merge remote-tracking branch 'yauhen/docker'
fix(docker): install libjpeg for pillow
SD-661 : On comment save detect if any user has been mentioned on comment and generate the notification
fix(ingest-provider) - fix adding ingest providers, create regression tests
SD-661 : On comment save detect if any user has been mentioned on comment and generate the notification

Fixed the user and comment checks on tests. Rewrite some for statements
on lists as list comprehensions.
SD-661 : On comment save detect if any user has been mentioned on comment and generate the notification
Merge pull request #237 from ioanpocol/master

SD-661 : On comment save detect if any user has been mentioned on commen...
Merge pull request #236 from amagdas/fix-add-provider

fix(ingest-provider) - fix adding ingest providers, create regression tests