Support uncoloured output across all commands

[radeksimko]

There was an attempt to implement this in the language server recently

https://github.com/hashicorp/terraform-ls/pull/208/files

but we didn't realize that some commands don't support the flag the same way others do - specifically terraform providers schema seems to need a special treatment. This then lead to reverting of that change in a subsequent bugfix release:

hashicorp/terraform-ls#226
hashicorp/terraform-ls#227

[radeksimko]

Actually this already happens in terraform-exec by default 😅 , which I suppose is sufficient - i.e. we probably won't ever need coloured output.

You are one step ahead already!