Canvas layout: port 'part_text' to Efl.Text.*

Canvas layout: port 'part_text' to Efl.Text.*

The following API is now supported with efl_part:

  - Efl.Text.text { set; get; }
  - Efl.Text.Cursor.cursor { get; }
  - Efl.Text.Cursor.cursor_paragraph_first;
  - Efl.Text.Cursor.cursor_paragraph_last;
  - Efl.Text.Cursor.cursor_position { set; get; }
  - Efl.Text.Cursor.cursor_coord_set;
  - Efl.Text.Cursor.cursor_line_char_first;
  - Efl.Text.Cursor.cursor_line_char_last;
  - Efl.Text.Cursor.cursor_char_next;
  - Efl.Text.Cursor.cursor_char_prev;
  - Efl.Text.Cursor.cursor_line_jump_by;
  - Efl.Text.Cursor.cursor_copy;
  - Efl.Text.Cursor.cursor_content { get; }
  - Efl.Text.Cursor.cursor_geometry { get; }
  - Efl.Text.Cursor.cursor_text_insert;

Many of the 'part_text' functionality was moved to legacy, too.
See the edje_object.eo to see which ones are still supported.