Update Platform Controls (#13751)

Continuing from #13597, this PR refactors platform controls to extract a
generic set of platform controls that can be used for any platform that
does not define it's own/we don't use the system ones.

In the future, these controls will likely be used as a fallback on
windows as well when the windows icon font isn't available.

Release Notes:

- Added updated window controls on Linux

assets/icons/generic_close.svg

@@ -0,0 +1,4 @@
+<svg width="16" height="16" viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
+<path d="M11.5 4.5L4.5 11.5" stroke="black" stroke-linecap="square" stroke-linejoin="round"/>
+<path d="M4.5 4.5L11.5 11.5" stroke="black" stroke-linecap="square" stroke-linejoin="round"/>
+</svg>

assets/icons/generic_maximize.svg

@@ -0,0 +1,3 @@
+<svg width="16" height="16" viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
+<path d="M11.5 4.5H4.5V11.5H11.5V4.5Z" stroke="#FBF1C7"/>
+</svg>

assets/icons/generic_minimize.svg

@@ -0,0 +1,3 @@
+<svg width="16" height="16" viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
+<path d="M4 8H12" stroke="black"/>
+</svg>

assets/icons/generic_restore.svg

@@ -0,0 +1,4 @@
+<svg width="16" height="16" viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
+<path d="M9.5 6.5H3.5V12.5H9.5V6.5Z" stroke="#FBF1C7"/>
+<path d="M10 8.5L12.5 8.5L12.5 3.5L7.5 3.5L7.5 6" stroke="#FBF1C7"/>
+</svg>