ENYO-2238: As an app developer, I can close all opened file on Designer and Code editor  

As @Iryna-Skakun-owo  comment on https://enyojs.atlassian.net/browse/ENYO-2238,
I've changed "Close All" scenario as showing savePopup for each edited file.

- Add 'closeAll" flag
- Reuse savePopup and remove saveAllPopup
- Call 'closeNextDoc' function after closing current file.
- In 'closeNextDoc' function, check 'closeAll' flag and if it is set 'true' then try to close next document. 
- Set closeAll to false when there is no more opened file or tapped 'Cancel" on savePopup.

Enyo-DCO-1.1-Signed-off-by: Juhyun Yoon <yunju123@gmail.com>