Add optional destination and player parameters to launch_rocket

[Gweneph]

Right now the LauEntity.launch_rocket() function doesn't take any parameters. So with Space Age enabled, when it launches a rocket, the contents are lost to the ether.
I'd like the ability to launch a rocket to a particular platform just like the launch cargo button allows.

Additionally, I'd like the ability to launch a player character just like the button on the silo UI allows.

These requests are for the Factorio Access Mod making alternative accessible interfaces.

(the make new platform button functionality is already available elsewhere.)

[ActionJackson]

+1

I'd like to also suggest that the dropdown that becomes visible when you click Launch Rocket to choose a destination is instead its own dropdown that's always available/visible that can be given its own RW point