add gsoc19 project: ios contact sync, invites (#1079)
add gsoc19 project: ios contact sync, invites (#1079)

* add gsoc19 project: rebrand android and ios apps

* remove trailing space1

* fix linter blank lines

* add gsoc19 project: ios contact sync, invites

* remove dup

* minor edits

* fix incorrect headers

RocketChat/Rocket.Chat.Docs,RocketChat/Rocket.Chat.Docs,RocketChat/Rocket.Chat.Docs,RocketChat/Rocket.Chat.Docs