Glob: Escape special characters in paths

Fix for CMake issue cmake/cmake#14789

This enhances Glob expressions to support backslash as an escape character. It also automatically adds escape chars to the portion of a glob expression that the user does not explicitly control (the full path to the location where the globbing will occur). This prevents unexpected globs, primarily for paths that contain square brackets since paths with '' or '?' will accidentally match themselves. Although paths with '' or '?' could in theory match many more paths than expected.