[vscode] API gap: Theia master vs. VS Code 1.64.2

[planger]

This bug tracks the differences between current master Theia VS Code API and VS Code 1.64.2:

• API Gap theia master vs. VS Code 1.55.2 #9863
• [vscode] Support CodeActionContext#triggerKind #11502
• [vscode] Support TerminalProfileProvider #11503
• [vscode] Support optional properties iconPath and color in TerminalOptions and ExtensionTerminalOptions #11504
• [vscode] Support specifying the location in terminal options #11506
• [vscode] TerminalLink turned into a class with constructor #11507
• [vscode] Support CancellationToken in file events #11508
• [vscode] Support querying whether file system and file stats are readonly #11509
• [vscode] Add Memento.keys() #11510
• [vscode] Support debug sessions being managed by a parent session #11511
• [vscode] Support optional property DebugSession.parentSession #11512
• [vscode] Support optional Pseudoterminal.onDidChangeName #11513
• [vscode] Support buttons in quick pick items #11514
• [vscode] Support indicating and notifying changes on Terminal.state #11515
• [vscode] Support type hierarchy view being populated by instances of TypeHierarchyProvider #11516
• [vscode] Support optional WebviewOptions.enableForms #11517
• [vscode] Support RelativePattern.baseUri #11518
• [vscode] TaskGroup misses support for id and isDefault #11519
• Stub vscode 'Tests' API #11717 (implementation deferred: Add tests namespace from VSCode API #10669)

[planger]

Fyi: I've pulled out the issue on the test API #10669, which we've decided to stub, into a dedicated umbrella issue that collects all the stubbed API (#12010). This is to avoid blocking to close this issue.