Tqdm: support global config to override defaults

[casperdcl]

1. look for e.g. "$HOME/.tqdm.config" to override defaults
2. alternatively/additionally use os.environ.get("TQDM_CONFIG", '')

helps with e.g. #370, #612, #619

The second (os.environ) option would be great to fix https://github.com/tqdm/tqdm/issues/370#issuecomment-421809342 (have tmux alter TQDM_CONFIG to have dynamic_ncols)

[chengs]

For #612, setting something like DISABLE_TQDM in ~/.tqdm.config may be too dangerous. A user may set it and forget this setting...

[faroit]

I agree with @chengs. This functionality is mostly useful for production servers where environment variables would sufficiently solve the problem

[ahundt]

I agree, this would be particularly useful for dynamic_ncols.

[ZeerakW]

Is there any update to this? I would tend to disagree with @chengs, I think if things are set from a tqdm.conf which needs to be manually created, people will look in that to identify the issue (specially if there's an instruction to see if the config file is creating the issue).
In any case, having a global solution as in #950 would be great as well and much easier than locally adding the same disabling code to all TQDM loops in ones code.

[acroz]

I would also very much like global configuration from either environment variables or a configuration file, but for the mininterval parameter.

I'd be happy to put together a short proposal of how either solution might be added to the library for discussion, and possibly also to open a pull request. @casperdcl is there willingness from yourself or other maintainers to include something like this in the library?