RFC: win32: nsis: compact installation after installation succeeds

Unlike traditional NTFS compression, compact.exe, introduced with Windows 10 works really fast and provides considerable compression rates with its default settings. For the record, it takes about 5 seconds to compress the whole installation with AMD Ryzen 5800H running under VM.

Nowadays decompression can be considered faster than reading from disk. So, it is almost always a good idea to utilize compression when applicable.

The size reduction observed during testing is substantial. The size reduction of vlc-4.0.0-dev-win64-c6566cf2 is as follows:

Before (size on disk): 252 MB (264,425,472 bytes) After (size on disk): 148 MB (156,147,712 bytes)