What:

Remove global references or make them explicit.

Why:

There might be problems with shadowed global variables in testing environments. See #892
The way e.g. jest hoists code we cannot be sure that a reference to e.g. window in a module is a reference to globalThis.window. We further cannot be sure that e.g. document.defaultView references the same object as window.
Although this is probably no issue in most cases we should be explicit about where we access objects through variables the user provided per setup() and where we access through global variables.

#929 , #931 enforce to be explicit about access to globals. Any reference that can't be found per text search for globalThis. results in a linting error.

How:

• Remove global references from Clipboard util. We already pass down window to the create functions so we can use the scoped variable in the class.
  We still access the global window for our afterEach and afterAll hooks to reset/detach the Clipboard stub. This is probably not an issue as the environments providing a global after* hook are probably identical to environments merging window into the global scope (like jest+jsdom).
  If you happen to use an environment where you need to work around this, please leave a comment.
• Make global references in setup() explicit. If the user provides a document with defaultView, these won't be used.
• Make global references (parseInt, setTimeout) in utils explicit.

Checklist:

• Tests
• Ready to be merged