Revert "elm_layout: Implement Efl.Text"

Revert "elm_layout: Implement Efl.Text"

This reverts commit 584e17ae84750b0c8a9bc92f41c767073a41fc94.

After talking to @herdsman (before xmas) we concluded that we
didn't necessarily want a generic version of efl_text_set/get
for elm_layout. Instead, each widget that should have a default
text part should implement text_set/get themselves (very simple).

Note that Efl.Ui.Text somehow does not "implement" efl_text when
looking at the eolian files. It works by composition.