Adding Key Rebind

When I was working on adding key rebind function today, I found out that key rebind didn't work properly in game because I was using generated C# Script from Input Actions for my player input handler. To fix this, I'll have to  rewrite my player input handler so that it uses Input Action asset instead of its generated script.

Turns out when I think something is easy and can be done in  30 minutes, there will always be something much harder beneath it, taking much more time than I anticipated.