Clarify Coding Standards

[abyrd]

The OTP project does have coding standards, but they are quite old and mostly consider code formatting style, rather than structural / architectural principles.

The OTP leadership committee has approved an effort to revise these coding standards, including references to external guidelines such as specific items in Effective Java.

@abyrd and @t2gran will draft this and submit it for approval as a pull request.

[t2gran]

This was approved by the PLC at the meeting at Thursday, April 18, 2019. See meeting notes for details.

[t2gran]

I am not sure how to proceed with this. There is several things to address (design, best practices, code style, and so on). I would like to do this in increments, so we don´t wait until the release of OTP2 to merge this. So my suggestion is to create PRs with some documentation - and possible code cleanup to go with it. Then this issue becomes some sort of ticket or epic for multiple iterations.

The first ting I would like to create a PR for is how to do application creation (dependency injection), this came up in the #2756 (Sandbox) Issue.

[tuukka]

Good idea to do multiple iterations - perhaps even postpone adding most "don'ts" until someone tries to do them first. The most important for now might be to mention anything special that either only exists in OTP or goes against other common style guides.