[Feature proposal] Gitlab omnibus package for arm64

Description

I think it will be useful to provide Gitlab CE omnibus package for arm64. There are a lot of raspberrypi-like boards with powerful arm64 SoC: ODROID-C2, Pine A64, ...

More than 95% of Debian repositories are ported to arm64 and are fully working. I checked and each Gitlab dependency is available on arm64: ruby 2.3, redis 3, golang 1.6, postgresql...

Proposal

Distribute Omnibus packages for this arch.