collapse functionality, modified sort behaviour, sort function modify

[kdcro101]

@leftstick ,

I've put whole day into this. Never developed extension before.. Lot of research done.... So..

What I learned today:

• adding context menu from File explorer to favorite item (and descendants) is probably imposible at moment
• Tree view is under heavily development

What I've modified/added:

• icon of sort action in title is changing depending of current sort direction.
• separated toogleSort to setSortAsc/setSortDesc
• modified sort algo to be more readable
• added collapse functionality - to collapse all opened nodes (to be more precise, i've improvised) See: https://github.com/Microsoft/vscode/issues/30918 - TreeView is generally unfinished feature

[leftstick]

see : https://github.com/leftstick/vscode-favorites/pull/10