WIP: Added changed state to IDE

What does this MR do?

Adds a changed state to the IDE store. The changed state keeps track of all the changed files & allows for files to be closed without loosing their current state.

To discard the files updated content the user will need to open the commit sidebar & click the discard button on the file row. Clicking this will reset the files state back to its original state & thus removing it from the changed files state.

Hovering over the row in the commit panels shows the discard button