feat: block launch if Java is incompatible

Keep track of compatible Java versions from meta. Launch-step
VerifyJavaInstall will check if current instance's Java version is
compatible.
Also add override option both globally and per-instance in-case the user
doesn't care about the requirement.

launcher/minecraft/VersionFile.h

@@ -57,6 +57,9 @@ public: /* data */
     /// Mojang: Minecraft launch arguments (may contain placeholders for variable substitution)
     QString minecraftArguments;
 
+    /// Mojang: list of compatible java majors
+    QList<int> compatibleJavaMajors;
+
     /// Mojang: type of the Minecraft version
     QString type;