FFM - FCM for Mojo-Webqq

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* Support Android P MessagingStyle, to fully use this feature, read the description below
* Android P styled theme
* Allow HTTP connection on Android P

Guide to let user avatar correctly show:
1. Update server part to 0.7.0
2. Setup account password login to let Mojo-Webqq fetch user uid (QQ number) correctly (https://github.com/sjdy521/Mojo-Webqq/issues/183)
3. Wait until all group members' uid (QQ number) is fetched
4. Use "Update avatar" in "Account settings" and wait
5. Enjoy