ElixirLS should detect . as the project directory and raise an error

[axelson]

elixirLS.projectDir having the value . causes the extension to not work. We should either ignore . or raise an issue

Results in an error like Skipping build because cwd changed from /home/jason/dev/gen_tracker/. to /home/jason/dev/gen_tracker in the output log

[fmterrorf]

Hi 👋 I'd like to take a stab at this issue. I see your comment here #427 (comment)

I agree that a warning would be a good improvement. Should we go even further and ignore a value of . replacing it with ""? (this would be in addition to the warning).

That would be done here correct? Where we'll check if the rootPath is . and replace it with ""

[lukaszsamson]

@fmterrorf I would not pollute this module with settings validation. Let's do it in server.ex in set_settings.