Use KLineEdit for folder name if folder has write access, else use QLabel

Summary:
T9297: 5th point
Use QLabel for "write" protected folder

Test Plan:

1. Open dolphin
2. Create two folders, one with write access and other with write access denied

Before:
All folders used KLineEdit for folder name

After:
Folder with write access uses KLineEdit
Folder with write access denied uses QLabel instead

Reviewers: rkflx, dfaure, ngraham

Reviewed By: dfaure

Subscribers: kde-frameworks-devel

Tags: Frameworks

Differential Revision: https://phabricator.kde.org/D14610