Comply with spec for permissions needed to delete a resource

Basically, until https://github.com/solid/web-access-control-spec/issues/47 gets discussed with a proper decision process, let's undo what was done in https://github.com/solid/node-solid-server/issues/729.

I'm not so fussed about the actual behaviour, I just want to start the process of documenting what we consider the spec (see also https://github.com/solid/solid-spec/issues/174), and on which points we are aware of differences between NSS and the spec.

Wherever such differences exist, if we think that NSS is right, then we should update the spec.
And if we think the spec is right (like in this case), we should (at least create a github issue to) fix NSS.

PS: If anyone is aware of any other points on which NSS is not spec-compliant, then let's create issues for each one of those. We can decide to willingly leave NSS broken, but at least we should have github issues that document how NSS is broken.

首先阅读链接的 web-access-control-spec issue 47、NSS issue 729 和 solid-spec issue 174，以比较删除资源所需的权限要求。issue 中没有指定文件或测试；完成标准是记录 NSS 与 spec 之间的差异并记录决定，如果需要更改实现，则创建后续的 NSS issue。