Display problems in groups (one at a time)

I see that we can disable linters in a `.vimrc` before invoking vim. However, it would be helpful to disable particular linters while already running vim.

Example: I'm using Pyright with CoC, with diagnostics displayed by ALE. Ideally, I could run ALE until I'm done with type checking, and then enable Flake8 linting. Right now, Flake8 and Pyright run together, and give many duplicate errors. It would make it easier to lint code if I could disable Flake8 linting until I'm ready to work with its output.