This uses the language server settings added in #9293 to allow users to
specify the binary path and arguments with which to start up `gopls`.
Example user settings for `gopls`:
```json
{
"lsp": {
"gopls": {
"binary": {
"path": "/Users/thorstenball/tmp/gopls",
"arguments": ["-debug=0.0.0.0:8080"]
},
}
}
}
```
Constraints:
* Right now this only allows ABSOLUTE paths.
Release Notes:
- Added ability to specify `gopls` binary `path` (must be absolute) and
`arguments` in user settings. Example: `{"lsp": {"gopls": {"binary":
{"path": "/my/abs/path/gopls", "arguments": ["-debug=0.0.0.0:8080"]
}}}}`