Use parser from vscode-css-languageservice for all files

[mrmlnc]

Use the vscode-css-languageaservice package as default parser for all files instead of scss-symbols-parser.

Pros:

• Maintainable solution by Microsoft VS Code team
• Stability

Cons:

• This will cause the primary scan to slow down, but will increase stability (Explore 'vscode-css-languageservice' as default parser for all files #92)

[mrmlnc]

As the first step I want to remove the symbols of the current document from the tooltips, because the original plugin (editor) does it.