Exit synadm early on fatal errors, refactor & fix query()

[JOJ0]

Addresses general error handling issues discussed in: #164

• What actually is a fatal error where it does not make sense to continue? I picked a few already. There might be more. Please suggest!
• Is it really a good idea to define log_fatal_exit() directly in this module as a regular function? Should it live inside ApiRequest? Or move it to a "utils-like" place? Will we use it outside this module too?
• Some refactoring along the way
• Add type hints (we can discuss if this is the right place and time....)
• Fix docstring
  • arguments done
  • return value: FIXME, isn't this entirely wrong? resp.json() returns lists or dicts. Or what does json string mean in this context? It's no string in reality....

[JacksonChen666]

• What actually is a fatal error where it does not make sense to continue? I picked a few already. There might be more. Please suggest!

I guess check for anything that logs errors and exits. Searching for raise SystemExit is a good starting point.

• Is it really a good idea to define log_fatal_exit() directly in this module as a regular function? Should it live inside ApiRequest? Or move it to a "utils-like" place? Will we use it outside this module too?

Maybe do move it to some utils place (tying into the last point)

• return value: FIXME, isn't this entirely wrong? resp.json() returns lists or dicts. Or what does json string mean in this context? It's no string in reality....

JSONs can also be strings, numbers, booleans, nulls, and the usually expected lists and dicts. In most (or even all) cases, it's dicts and possibly lists. So it can be kind of anything, but for specific API methods, we might as well just infer from the example output in Synapse Admin API docs, and for the query function, just JSON decoded I guess (noting that other types are possible too).

[JacksonChen666]

Looked at it, made some commits. Hope to get some feedback on some of my commits, if any.

[JOJ0]

Good to go? @JacksonChen666

[JOJ0]

Good to go? @JacksonChen666

Ah moving to utils place......but actually: We don't have a place for it. I'd rather not invent one now. We do that if we ever need it elsewhere. Agreed?

(we only have _helper.py and _common.py in package cli which is not imported here, so...)