Fixed #22796 -- Added more basic explanations of forms

Now explains some more basic form handling before discussing Django;
simplifies initial examples; defers explanation of more advanced
aspects until later in the document
"form, because -> "form because" (no coma). See [here](https://www.noslangues-ourlanguages.gc.ca/bien-well/fra-eng/ponctuation-punctuation/avant-before-eng.html) or [here](http://www.dailywritingtips.com/5-calls-for-a-comma-before-%E2%80%9Cbecause%E2%80%9D/).