Remove make install

Overview

I think it's time to remove make install. I never really used it and I see it only from time to time, when someone reports problem like in https://gitlab.slack.com/archives/CBQ76ND6W/p1578345133052300. It's confusing because people - which is obvious - expect that make install will install all that is required. While it's not installing but compiling and it's doing this in the most simple way that doesn't include building helper images and/or other build parts that Runner needs in most cases. For local development/tests we should really use make build_current and if someone is 100% sure that helper images and other stuff is not needed - make build_simple. This uses the same mechanisms as official releases. If someone wants to install, then... well it depends on the used OS and distribution and for that we have a detailed docs.

Proposal

remove make install
Update docs to specify to use make build_burrent & make build_simple explaining the difference both.