findNvim should work without $PATH

[justinmk]

Problem

findNvim currently depends on $PATH. That makes it less useful for GUIs where the $PATH may be missing some common nvim install locations. https://github.com/neovim/node-client/pull/207/files#r1265953052

Expected behavior

Search for nvim in common locations, e.g.

/usr/local/bin/
/usr/bin
/opt/homebrew/bin
/home/linuxbrew/.linuxbrew/bin
$HOME/.linuxbrew/bin
$HOME/bin

as well as any others that we possibly can, such as the install locations for https://github.com/microsoft/winget-cli and https://scoop.sh/ on Windows, if possible.

Also...

Capture time cost for each search step and report that in the result? https://github.com/neovim/node-client/pull/207/files#r1264587700