Reorder the README so newcomers see the product before the philosophy:
CLI demo and web UI up top, a "Try it in 5 minutes" section linking the
GNS3 and build-from-source guides, then hardware and the rest. Tone
down the remaining marketing prose in the hardware and use-case lists.
Rename CODE-OF-CONDUCT.md to CODE_OF_CONDUCT.md so GitHub recognises it
as the community code of conduct, and link the .github/ health files
from the README.
Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
