cockroachdb: 2.0.0 -> 2.1.1, aarch64 support

This also splits the .bin output to have a separate .man attribute:
previously it contained both.

This also adds provisional support for aarch64-linux, which seems to
build easily. (Full testing will ideally come via NixOS tests later)

Signed-off-by: Austin Seipp <aseipp@pobox.com>