add /debug endpoint

[evanugarte]

we need an endpoint called /debug which can return quick information about the server's state and code that its running. an example response should look like

{
  "scetv_githash": "17ae119",
  "scetv_gitbranch": "dev",
  "scetv_gitdirty": 0,
  "state": {
    "process_dict": { },
    "current_video_dict": { }
  },
  "cache": { }
}

game plan

• [x] define /debug endpoint that returns a json object
• [x] add a state field to the json object that has one field called "process_dict" and another called "current_video_dict" which we can set to the value of both variables. ensure the endpoint returns the value of these dictionaries when called
• [x] once the above is done, add a "cache" field. this should return the verbose value of the cache variable. to do this i think we can just do vars(cache)? https://www.geeksforgeeks.org/vars-function-python/
• [x] find a command to get the short hash for the latest commit on the branch https://stackoverflow.com/a/949391
• [x] find a command to get the name of the current git branch https://stackoverflow.com/a/6245587
• [x] find a command to check if there are any "stray" uncomitted changes with git. if so, we would set scetv_gitdirty to 1. for now just find a command, the 0/1 stuff work with evan on
• [ ] to add the git fields above work with evan on this, we will likely need to set some environment variables before running the server.