ox-html: Use options instead of hard-coded variables

ox-html: Use options instead of hard-coded variables

* contrib/lisp/ox-s5.el (org-s5--format-toc-headline): Apply signature
  change.

* lisp/ox-md.el (org-md-headline): Apply signature change.

* lisp/ox-html.el (org-html-format-drawer-function,
  org-html-publish-to-html): Small reformatting.

(org-html-infojs-install-script, org-html--build-meta-info,
org-html--build-mathjax-config, org-html-format-spec,
org-html--build-pre/postamble, org-html-template, org-html-toc,
org-html--format-toc-headline, org-html-list-of-listings,
org-html-list-of-tables, org-html-bold, org-html-drawer,
org-html-headline, org-html-inlinetask, org-html-italic,
org-html-checkbox, org-html-inline-image-p, org-html-link,
org-html-section, org-html-strike-through, org-html-table-cell,
org-html-table-row, org-html-underline, org-html-verbatim,
org-html-final-function, org-html-export-to-html): Do not use
hard-coded variable names.

(org-html-format-headline-function,
org-html-format-inlinetask-function): Change default value.  Require
an additional argument.

(org-html-format-footnote-reference,
org-html-format-footnotes-section,
org-html-format-footnote-definition, org-html-format-headline,
org-html-format-headline--wrap, org-html-format-section): Remove
functions.

(org-html-footnote-section, org-html-footnote-reference): Apply
function removal.  Do not use hard-coded variable names.

(org-html--anchor, org-html--todo, org-html--tags): Change signature.
Do not use hard-coded variable names.

(org-html-radio-target, org-html-target): Apply signature change.

(org-html-format-headline-default-function,
org-html-format-inlinetask-default-function): New functions.