Copy and paste web page designer controls between pages, projects, and sessions

The web page designer's clipboard only worked inside a single page: copying a control on one page and switching to another left Paste unavailable. The desktop designers share their clipboard through the system clipboard as text, so copies travel between windows, projects, and Studio sessions. The web page designer should do the same: Copy and Cut place the selected controls (or Timer) together with their event handlers on the system clipboard in a serialised web format, and Paste on any web page — in the same project, another project, or a fresh Studio — inserts copies with fresh identities, unique names, and renamed handler clones.