display: Move glyph definition to printer config

This commit allows to modify the icons (or glyphs) in the displays that
support it. Existing icons can be modified and new icons can be added via
a [display_glyph] section in the config.

Signed-off-by: Florian Heilmann <Florian.Heilmann@gmx.net>

klippy/extras/display/hd44780.py

@@ -95,6 +95,8 @@ class HD44780:
             data = data[:20 - min(x, 20)]
         pos = x + ((y & 0x02) >> 1) * 20
         self.text_framebuffers[y & 1][pos:pos+len(data)] = data
+    def set_glyphs(self, glyphs):
+        pass
     def write_glyph(self, x, y, glyph_name):
         char = TextGlyphs.get(glyph_name)
         if char is not None: