Allow to configure path to bash-language-server

[felixfbecker]

When using a version manager like nvm VS Code will not have the npm I am using in the PATH, only the shell. Since I have many versions of node/npm installed, I would like to tell the VS Code extension to use a specific one. This could also be useful for debugging.

[mads-hartmann]

@felixfbecker This is a great idea. I'd be more than happy to accept a PR adding it 👍

[mads-hartmann]

@felixfbecker I've added a configuration option now named bashIde.path that you can use to set the location of the binary to use