Add release notes for 1.2.0 and 1.1.1

Add release notes for 1.2.0 and 1.1.1

This is a manual cherry-pick from multiple changes in the tizen_3.0
branch:
- Add Tizen Studio 1.2.0 release notes (#125852)
- Edit emulator fixed bug change in RN 1.1.1 (#126434)
- Update Emulator changes in Fixed Bugs section (#116555)
- Add Release Note for Tizen Studio 1.1.1 (#113675)

PS2: Manually cherry-picked "Update 1.2.0 release date and numbering"
change (#128463) from the tizen_3.0 branch
PS3: Manually cherry-picked "RT IDE does not support debugging,
modify the RN." change (#128256) from the tizen_3.0 branch

Change-Id: Ia16a4ae985b8fd10616783f346b88c8a7c038c08