Allow ability to disable linting and error detection for jsonnet language server

[zzehring]

There's a common problem with large codebases with the language server where the language server consumes tons of memory (20-30GB) primarily due to live linting and error detection.

In the VSCode extension, it's possible to disable those and avoid this memory issue. The same options should be available in this plugin.

So we need to:

• Provide UI options for enabling/disabling linting and error detection
• Handle passing those corresponding arguments when running the language server binary
• ?
• Profit

[zzehring]

Done in #80. Will be released in v0.2.0.