add next/submit.html and improve FAQ and other refs to entering the IOCCC

Added a new `next/submit.html` to move the "how to submit" form "in-line"
of the top FAQ entry into a new page managed by `next/submit.md`.
Thus, `next/submit.html` is a parallel to `next/register.html`
and `next/submit.md` is a parallel to `next/register.md`.

Changed the FAQ "faq.html#submit" and into "faq.html#enter".

Added individual tags for the steps in FAQ0.0.

Moved "faq.html#register" down to FAQ 0.0 step 2.

Added "faq.html#submit" for FAQ 0.0 step 5,
however elsewhere often "next/submit.html" is used.

Changed references for "faq.html#upload" to "next/submit.html".

We made a number of changes to the following markdown files to reflect the above:

- `about.md`
- `faq.md`
- `index.md`
- `markdown.md`
- `next/README.md`
- `next/README.md`
- `next/guidelines.md`
- `next/register.md`
- `next/rules.md`
- `nojs-menu.md`
- `status.md`

as well as these files:

- `bin/gen-top-html.sh`
- `bin/md2html.cfg`

and added:

- `next/submit.html`
- `next/submit.md`

Perform `make www` and `make gen_status` to perform the above and test under macOS.

TODO: Add images about the mailing list to `next/register.md`.  See the line:

```
XXX - **put images and other details about joining the mailing list here** - XXX
```

markdown.html

@@ -450,7 +450,7 @@ start with some markdown content.</p>
 <p>See the <a href="https://www.markdownguide.org/basic-syntax">markdown syntax</a> guide.
 See also the <a href="https://spec.commonmark.org/current/">CommonMark Spec</a>.
 See the
-FAQ on “<a href="faq.html#submit">how to submit</a>”.</p>
+FAQ on “<a href="faq.html#remarks_md">remarks.md submission file</a>”.</p>
 <p>Nevertheless, the IOCCC does have certain practices that we ask authors to follow.
 Some of these relate to use of markdown directly and others relate to injecting HTML
 into the markdown file.</p>