Implement file/folder excludes

We should implement the exclusion of files/folders in the explorer view.

• in the explorer view, excluded files should be visualy marked (font/color/icon, whatever)
• list of excluded resources should be saved in a file
• on changes, the lsp server should be notified
• set commands accessibility and keybindings
• tpd file parsing: validation, included/excluded folders
• handle selected tpd file changes
• saving last state before switch
• handle default vscode exclude settings

The server expects the following json request:

"excludedStates": [
	 {
	 	"identifier": { "uri": "file:///whateverA" },
	 	"isExcluded": true
	 },
	 {
	 	"identifier": { "uri": "file:///whateverB" },
	 	"isExcluded": false
	 }, ...
]