Add enable disable command

[CGQAQ]

Depends on #196, Please review it first

Show enable command when lsp is disabled, disable command when lsp is enabled

Part of roadmap 2 (#194)

Closes #170

[CGQAQ]

@bartlomieju @axetroy @lucacasonato Ready for review

[David-Else]

I remember this addition was debated before in the old extension and removed. I like the idea, but my only reservation is that now there are more options, logically they should be togglable as well? Perhaps instead Init Deno project creates and opens:

// .vscode/settings.json
{
  "deno.enable": true,
  "deno.unstable": true,
  "deno.lint": true,
}

This could be a nice time-saver? It would force people to make decisions on these options right away, and educate them that they exist.

[CGQAQ]

I think to add every config to command is not a good idea

[axetroy]

I think to add every config to command is not a good idea

as I said. #170 (comment)

Consider adding a deno.init or deno.setup command for configuration.

[CGQAQ]

Don't need anymore