Compilation with the default settings failed when downloading PCSX2 into
a directory with spaces somewhere in its path:
* In CompileGResources.cmake the paths had been escaped already, resulting
in double escaping the strings (i.e. embedding them in quotes _and_
escaping spaces with a backslash. cmake wasn't able to parse the line
any more.
* In pcsx2/CMakeLists.txt the paths were not escaped, but also not
embedded in quotes, resulting in an invalid Bash command.
This commit fixes these cases (but is neither a review to find all cases
or making sure other characters such as a newline character would work).