Option to set save location in-game

[Jap2.0]

TL;DR

Add an option in-game to change the location of saves, so that we don't have to muddle through configs and confusing directions to change this.

What?

Right now, if you want to change the location of where your saves are, you have to muddle through conifg files with slightly confusing directions. Some people might not even know that this is an option in the first place. I bought the game through Steam, and the game installed in my Steam folder (in the G:\ partition, right where I wanted it), while my saves, mod information (just an empty mod list at the moment), logs, etc. went in %appdata%/factorio. This cluttered up the C:\ partition. Changing it was a complicated mess of looking through very old forum topics, the wiki, config files with long instructions all cluttered on one line, and a lot of trial and error (note that I did figure it out eventually, so I don't need help with that). I would also appreciate if the save location wasn't reset if this is ever included in the game. Finally, it would be nice to have an option to transfer your save files from their old location to the new one automatically if this is ever done.

Why?

This is just a nice quality of life change that would help to inform players that this is an option and make it easier for everyone - especially those who are bad with computers, but even those who aren't.