Don't rely on `replace` in make.

replace is actually not a common Unix utility,
but a part of MySQL server. Instead, use sed.
Make configure use arguments instead of prompts.

./configure is normally a non-interactive script
that accepts all its data via command-line arguments
and options. That's what this patch does.
Depend on .config.status.
Make index.html into a template (#8).

The index.html file is now gone and replaced by
a template file; it is generated by make.

This allows automatically adapting the file to HTTPS,
configuring the page title and setting a logo URL.

(Some other optimizations were made to the Makefile and
configure script.)
Move logo to img/logo.png