upx is nice, but not necessary for this and duplicating Makefile is just not
good.
Note that in absence of vendoring building this can be problematic at the
moment because of private repository dependency, it'll be solved in future.
- set output for flag set
- change env prefix for all environments
- migrate to CDN SDK release v0.1.0
- update README
Signed-off-by: Evgeniy Kulikov <kim@nspcc.ru>