Libraries: Make CharacterBitmap instances at compile-time

`CharacterBitmap` instances are generated at run-time and put on the
heap, but they can be created in a `constexpr` context and stored in
static memory.

Also, remove additional `width` and `height` `static` values in favor
of using the `constexpr` member functions of `CharacterBitmap`.

These changes also include the removal of some initialization code
which tests if the `CharacterBitmap` is created since it is always
created and removes function-local `static` values which cause
run-time branches to ensure it is initialized each time the function
is called.

Userland/Libraries/LibGfx/CMakeLists.txt

@@ -6,7 +6,6 @@ set(SOURCES
     BitmapFont.cpp
     BMPLoader.cpp
     BMPWriter.cpp
-    CharacterBitmap.cpp
     ClassicStylePainter.cpp
     ClassicWindowTheme.cpp
     Color.cpp