refactor(language-core): generate global types in one virtual file

[johnsoncodehk]

This is a redo of #3534.

• The language server designates the first virtual file as the global types holder when it generates the first virtual file, and generates the helper types on it.
• vue-tsc creates additional dummy .vue files as global types holders to avoid global types emit to dts.
• Each project's global types holder is known at the time of generating virtual files. Using the holder file name as the file registry key safely avoids conflicts caused by duplicate helper types when multiple projects in the repo share virtual files.
• When the global types holder file is deleted, the global types holder is switched to another random file in the file registry (d4c0c5e)