Allow ignoring of conform configuration

[liveforeverx]

I don't know, if it is best solution. But, sometimes you don't want to generate sys.config.

Use case, implementing CLI with commands or escript, so and you want to allow another users to execute commands. If sys.config will be replaced by another user, the release willn't be startable. To prevent this, I propose to introduce CONFORM_IGNORE environment.

If there is better solution, I would like to know.

[liveforeverx]

Ok, so it is not enough, I need to change it in distillery

[liveforeverx]

Related, using the same environment: https://github.com/bitwalker/distillery/pull/360