Improve (notification) service featureset

[canihavesomecoffee]

Currently PiPot only allows the user to upload a single file that holds all the data the service needs. This approach has benefits, but also some disadvantages:

• Private dependencies or unlisted programs (from source code) can't be installed
• All template code is in a string inside a method in the service class
• No javascript libraries can be added

Switching from a single file to an custom format or zip based container would solve these issues.

[VertexC]

The current server supports container upload, while doesn't handle the pip installation and requirement check. # For requirement installation, here is the code for the reference, but ideally valid the dependencies before install that into virtual environment. PiPot/pipot-server#33