Probe tools cli

[fendor]

For making #305 simpler

Example:

> haskell-language-server --probe-tools
haskell-language-server version: 0.3.0.0 (GHC: 8.8.3) (PATH: /home/munin/.cabal/store/ghc-8.8.3/haskell-language-server-0.3.0.0-50ac3c2ce9988216a5f58c897e446f023d24f554e742bcae93fcc77e9a6ded73/bin/haskell-language-server)
Tool versions found on the $PATH
cabal:		3.0.0.0
stack:		2.1.3.1
ghc:		8.8.3

>  haskell-language-server .
haskell-language-server version: 0.3.0.0 (GHC: 8.8.3) (PATH: /home/munin/.cabal/store/ghc-8.8.3/haskell-language-server-0.3.0.0-50ac3c2ce9988216a5f58c897e446f023d24f554e742bcae93fcc77e9a6ded73/bin/haskell-language-server)
(haskell-language-server)Ghcide setup tester in /home/munin/Documents/haskell/hls.
Report bugs at https://github.com/haskell/haskell-language-server/issues

Tool versions found on the $PATH
cabal:		3.0.0.0
stack:		2.1.3.1
ghc:		8.8.3


Step 1/4: Finding files to test in /home/munin/Documents/haskell/hls
Found 467 files
...
<truncated>

[Ailrun]

Awesome!

[horus]

Correct me if I'm wrong, I think this does not play nicely with projects bootstrapped with stack:

Cradle type: Default
haskell-language-server-wrapper: ghc: readCreateProcessWithExitCode: runInteractiveProcess: exec: does not exist (No such file or directory)

The path to the ghc executable is not necessarily included in $PATH.

[fendor]

@horus Indeed, my mistake, for some reason I assumed this would be covered by readCreateProcessWithExitCode
Fix in progress