Efl.Ui.Text: Fix Text Cursor composition

Efl.Ui.Text: Fix Text Cursor composition

Summary:
This is a temporary fix while Text is being revamped.
Efl.Ui.Text internally composites Efl.Text_Cursor (through some other interfaces)
but this was not being advertised in the EO file.
This caused no trouble to C but was preventing C# from using the Cursors API
(because C# relies on the EO composites section).

On top of this, the cursor_new() method has been removed, since it was redundant.

Test Plan:
Builds and passes tests, and C# is able to do things like:
```
Efl.TextCursorCursor cursor = screen.GetTextCursor(Efl.TextCursorGetType.Main);
screen.InsertCursorText(cursor, str);
```

Reviewers: lauromoura, cedric, tasn

Reviewed By: lauromoura

Subscribers: #reviewers, #committers

Tags: #efl

Differential Revision: https://phab.enlightenment.org/D10465