Port hreflang tokens to D8

Just wanted to report that #33 fixed this issue for us.

Moving this to the v2 branch.

The patch from #33 also works for us.

Test coverage is missing, so leave it at needs work

The MR seems to be empty.

• Converted to MR and confirmed in tests that tags are displayed.
• Not sure how far you want to take token tests. I can't quite wrap my head around the TokenTestTrait at the moment.

scott_euser → changed the visibility of the branch 8.x-1.x to hidden.

scott_euser → changed the visibility of the branch 2.1.x to hidden.

scott_euser → changed the visibility of the branch 2956982-port-hreflang-tokens to hidden.

Further updated if you use `[node:url-LANGCODE]` you will get a fatal error otherwise because ->url() exists on translation but ->toUrl() is needed for entity interface