More manual conversion of index based for loops to for-of loops

Use `Array<T | U>` when dealing with union types instead of  `(T | U)[]`

We compile using the alwaysStrict flag so these directives are not needed

This part removes most `use strict` directives that are right after the file header

This reverts commit 27256832 which turns out did not break the import of vs/nls

This reverts commit 7de696a2.

Seems to have broken loading vs/nls in at least one case in insiders

Don't use this import form in places where it is not needed. This prevents us from correctly detecting duplicate imports

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

* introduce IRelativePattern and use in extension API

* 💄

* docs

* introduce RelativePattern

* support RelativePattern also for file watcher

* also make findFiles support RelativePattern

* less type conversion

* add GlobPattern type and remove readonly

* make base a string

* fix setter access to RelativePattern

* fix npe when exclude is undefined

* fix findFiles: pattern seems to be matched against workspace always

* 💄

* clarify glob pattern matching

Fix exclude settings to be resolved against their root folder, not the searchPath, mainly for './' search scenarios