Yes, you can set up rally points for your ships to go to. Just press your P key or look for the icon on your interface that says Add Rally Point. If you have one set, then you can assign each planet to it which will auto-launch your ships for you. When a planet is selected, look for a yellow button on the interface, just a bit off to the left hand side. This will let you select any rally point you want for that planet, they'll all be listed in the box that appears. With a rally point selected, any ship built on the planet will automatically head to the rally point and launch itself.

As for Constructors, there's lots of complaints at the micro-mananagement involved at building space stations. However you can simply things quite a bit by having a planet building nothing but Constructors and assigning a rally point to the base your want to build. When the ship is built, it will automatically head for the rally point and build the module when it arrives. It's not a perfect system by any means, you'll notice certain shortfalls when you work with it, but it's better than doing everything manually.

Below the news icons on the right hand side of your screen, there's a little arrow that says "launch all newly constructed ships." I employ it regularly