Instead use NativeImage on 1.13+ via newly introduced Image class.
See Image docs for details.
Also fixes an issue with thumbnail taking on 1.13+: The original
ScreenshotHelper method is now async, luckily there's a sync
variant and as a bonus it directly returns a NativeImage so we can
skip having to read the screenshot from disk.
JREs prior to 8u101 do not ship with the root certificate that cross-signed
the LetsEncrypt X3 CA used to sign server certificates.
As the standard native Minecraft launcher for Windows and OSX ship with an
older Java version, this commit imports the required root cert and uses it
wherever communication with the replaymod.com server is established.
Effectively reverts 682fb4b
