Add support for 2 channel/gang curtain module j1xl73iw

[tfoldi]

This PR is what is seems, it support two channel curtain module (like j1xl73iw). As it requires a submodule to control both channels, I created a new device folder for it.

Any comments are welcome.

I have one issue that I might need to change: on the primary module, the state states UP and DOWN and set position work correctly, but the OPEN and CLOSE do not. On the submodule, all three methods work well.

Still, it does the job, up and down works, set to % also.

This will fix #362 as well