Added MAINTAINERS to top-level repo directory
Added MAINTAINERS to top-level repo directory

In a consensus reached in a proposal for code review process
change [1], and proposed team structure policy document [2],
adding MAINTAINERS files in repositories.

Please note, that this file is written in YAML format in order
to allow further automation around code review process.

[1] http://lists.openstack.org/pipermail/openstack-dev/2015-August/072406.html
[2] https://review.openstack.org/#/c/225376/1

Change-Id: I07038f2fc173c184c1a72d61675b3207a08ddb44

huntxu/fuel-main,eayunstack/fuel-main,eayunstack/fuel-main,stackforge/fuel-main,stackforge/fuel-main,eayunstack/fuel-main,SergK/fuel-main,huntxu/fuel-main,huntxu/fuel-main,SergK/fuel-main,SergK/fuel-main,stackforge/fuel-main