GH-1795 add terminal launch option to use a specific Minecraft profile

Used like this:
```
./MultiMC --launch 1.17.1 --profile MultiMCTest --server mc.hypixel.net
```

launcher/minecraft/launch/MinecraftServerTarget.cpp

@@ -17,6 +17,7 @@
 
 #include <QStringList>
 
+// FIXME: the way this is written, it can't ever do any sort of validation and can accept total junk
 MinecraftServerTarget MinecraftServerTarget::parse(const QString &fullAddress) {
     QStringList split = fullAddress.split(":");