stripped obsolete features and compacted UI

1.7.0

- remove: Obsolete operators and panels
  - Remove "line closer" panel as it's been a native tool for a while in 2.9x (stop register of `GP_guided_colorize > OP_line_closer`)
  - Remove "Render" subpanel, obsolete and not adapted to production
- ui: clean and refactor
  - Gp clipboard panel and aimation Manager subpanel layout to aligned columns (gain space)
  - add `GP` on each panel name for wuick eye search
  - follow cursor now in animation manager subpanel (should be in an extra menu or removed in the end)

OP_copy_paste.py

@@ -637,13 +637,16 @@ class GPCLIP_PT_clipboard_ui(bpy.types.Panel):
 
     def draw(self, context):
         layout = self.layout
-        row = layout.row(align=True)
+        
+        col = layout.column(align=True)
+        row = col.row(align=True)
         row.operator('gp.copy_strokes', text='Copy strokes', icon='COPYDOWN')
         row.operator('gp.cut_strokes', text='Cut strokes', icon='PASTEFLIPUP')
-        layout.operator('gp.paste_strokes', text='Paste strokes', icon='PASTEDOWN')
-        layout.separator()
-        layout.operator('gp.copy_multi_strokes', text='Copy layers', icon='COPYDOWN')
-        layout.operator('gp.paste_multi_strokes', text='Paste layers', icon='PASTEDOWN')
+        col.operator('gp.paste_strokes', text='Paste strokes', icon='PASTEDOWN')
+        # layout.separator()
+        col = layout.column(align=True)
+        col.operator('gp.copy_multi_strokes', text='Copy layers', icon='COPYDOWN')
+        col.operator('gp.paste_multi_strokes', text='Paste layers', icon='PASTEDOWN')
 
 ###---TEST zone