Refactor Collection with HTTP GET Requests. Closes #272

[umesh-timalsina]

I have refactored the data collection mechanism in chimerapy-engine with the following changes:

• The manager requests collection using HTTP post, and waits for the FSM to change to "SAVED"
• A collect Event is emitted through the post request.
• The record service teardown, then emits an ArtifactEvent with the necessary metadata needed to serve the file with HTTP GET from the worker's server.
• The manager, then requests this information, and a series of aiohttp file download utilities are fired to download/copy move files

Todos

• Test Long Running Pipelines
• Support Images as zipped directory
• Hash Checksums?
• CleanUp old functions