Add support for Snuba settings

[emmatyping]

Coming over from https://github.com/getsentry/snuba/issues/2884

@lynnagara asked:

I would prefer for us to find a way to make it easy for self hosted users to configure their settings instead of adding back the CLI arg here, as it is likely to come up again for other settings that people might want to tweak.

So this issue is to track making it easy for users to change snuba settings in self-hosted.

[lemens]

Its almost a year now, any new infomation for this issue can share? 22.10.0 stuck for this ..

[azaslavsky]

Not at the moment, I'll surface this to the self-hosted team to discuss further.