Change New Maximized Window to Resizable от jscher2000

Inspired by https://support.mozilla.org/questions/1274624.

Version 0.5 adds a new toolbar button to set a default position and size for new resizable windows if you don't like where Firefox is placing them. Too many buttons? To remove an add-on button, either:

• right-click > Pin to Overflow Menu
• right-click > Remove from Toolbar