add a new lifecycle event `Restoring` which is set when the editors/viewlets are being restored (start). also in the lifecycle service replace `onDidChangePhase` with `when`

fixes #37559

With TS 2.6's strict functions mode, you cannot use a subclass in place of a parent parameter type in a callback

TS cannot properly infer the types in this case

WIth strictFunctions, the callback can no longer use implicit casts to a subclass for parameter types. This pattern was widely used with `.on` event callbacks in the dom

rename startupTimer to performance, support mark and measure, drop promise support, add more marks to slowly phase out old timers

fixes #37694