[RFC] CONTRIBUTING.md: describe adoption/orphaning policy and procedure

[classabbyamp]

I think it would be good to codify some of this. Open to suggestions on everything.

@void-linux/pkg-committers

[icp1994]

package instead of template sounds more natural to me.

[classabbyamp]

template is used throughout most of the rest of the document

[Vaelatern]

Please remember all we are not codifying package adoption and orphaning in code. We're trying to codify the process in a little way so we don't see people adopt a package in their first ever contribution, taking over from an active maintainer.

[classabbyamp]

feedback incorporated