Windows bootstrap

[WcaleNieWolny]

Currently windows users have to setup FFmpeg manualy. This is bad because it requires user to follow a complicated guide. We need to create an easy way to automatically install FFmpeg. My idea:

1. Try to load library normally
2. if it fails check if a "bootstrap" option is enabled in config
3. If so load a rust windows bootstrap lib
4. in this lib we will check if FFmpeg is downloaded if so go to step 6
5. Download and unzip prebuilt FFmpeg
6. Call SetDllDirectoryA to add FFmpeg bin folder to path temporary
7. Use libloading to load the lib
8. If it succeed use get the library symbols and use register_native_methods to register native JNI method
9. If nothing failed return to java. If something failed throw an exception

[WcaleNieWolny]

Merged Into merge a while ago