microflyer: tagline restoration combined with phrasing, font family and table spacing adjustments

With these changes in place I think I'm ready to gather further feedback from debian-doc.

Preview screenshot below:

Debian is a free operating system for computers of all
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tions, including software for businesses, programmers,
scientists, educators and artists.

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are provided by a community of more than a thousand
volunteers with subject area interest and expertise in
the software they maintain – and all of the source code
for that software is available for you to read, edit and
redistribute.

To learn about Debian and to obtain a copy that you
can run and optionally install, scan the QR code above
or visit the website: https://www.debian.org