[Twig] Have `getSiblings` / `getParent` / `getParents` / `getChildren` functions to work properly with the contenttype rules

[xiaohutai]

If possible

[xiaohutai]

I'm not sure contenttype rules are nice to have tbh. They're more or less a nuisance to me.

It kind of makes sense, but it's a step extra to get it working with the current features (such as the tree view).

This may be an example:

• /home
• /portfolio
  • /portfolio/project-foo -- e.g. contenttype: projects
  • /portfolio/project-bar -- e.g. contenttype: projects
  • [...]
• /about-us
  • /about-us/accolades
  • /about-us/member/xiao-hu-tai -- e.g. contenttype: members
  • /about-us/member/john-doe -- e.g. contenttype: members
  • [...]
  • /about-us/blog -- e.g. blogposting listing (for a root /blog no extension is needed)
  • /about-us/blog/dolor-sit-amet -- e.g. contenttype: blog posts
  • /about-us/blog/lorem-ipsum -- e.g. contenttype: blog posts
  • [...]

For smaller sets it's may be easier to use the query rule, and do:

    - type: query
      params:
        query: "projects"
        parameters: { limit: 100, order: 'title' }
        parent: "page/2"

    - type: query
      params:
        query: "members"
        parameters: { limit: 100, order: 'title' }
        parent: "page/3"

    - type: query
      params:
        query: "blog"
        parameters: { limit: 1000, order: '-datepublish' }
        parent: "page/3"

[xiaohutai]

Moved this to later. This feature makes it a bit less elegant and needs way more checks to get it right. Not even sure If I'm going to do this one.

[xiaohutai]

Wontfix for now. I think contenttype rules are a bit non-transparant.