org-element: Add `:post-affiliated' property to elements when applicable

org-element: Add `:post-affiliated' property to elements when applicable

* lisp/org-element.el (org-element-center-block-parser,
  org-element-drawer-parser, org-element-dynamic-block-parser,
  org-element-footnote-definition-parser,
  org-element-plain-list-parser, org-element-property-drawer-parser,
  org-element-quote-block-parser, org-element-special-block-parser,
  org-element-babel-call-parser, org-element-comment-parser,
  org-element-comment-block-parser, org-element-diary-sexp-parser,
  org-element-example-block-parser, org-element-export-block-parser,
  org-element-fixed-width-parser, org-element-horizontal-rule-parser,
  org-element-keyword-parser, org-element-latex-environment-parser,
  org-element-paragraph-parser, org-element-src-block-parser,
  org-element-table-parser, org-element-verse-block-parser): Add
  `:post-affiliated' property to elements.
(org-element-inlinetask-parser): Remove affilated keywords.
* lisp/org.el (org-adaptive-fill-function): Use new property.

This property is cheap to compute during parsing and allows to
determine if point is on an affiliated keyword or not by checking if
it is between :begin and :post-affiliated positions.