Return ID in parser function

[malberts]

For #23

• Use repo to get the ID
• Removed parser tests
  • I need to be able to save a page and get a real page ID. I couldn't find an easy way to do that and spending more time on that is not worth it.
• Added PHPUnit tests instead

Parser function returns:

Same as page information:

[malberts]

I ran into one issue here: the parser function value is not saved if the page is created with {{#ppid:}} inside. If the page content is purged, or changed later, then the value shows up.

I suspect this is always going to be a problem because it needs to save the page (and therefore its content) first before getting the ID. I'm not sure if there is another hook that can be used, or if we should trigger a purge if the page contains the parser function on creation.

[JeroenDeDauw]

if we should trigger a purge if the page contains the parser function on creation.

I can't think of a better solution

[JeroenDeDauw]

Follow ups:

• https://github.com/ProfessionalWiki/PersistentPageIdentifiers/issues/30
• https://github.com/ProfessionalWiki/PersistentPageIdentifiers/issues/31