Update README to include Openwrt branding and improve wording.

Point at the Openwrt wiki in .github templates.

Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>

Keep the link to submitting patches for now.

Signed-off-by: Stijn Tintel <stijn@linux-ipv6.be>

This text is used by GitHub to remind important things to
people sending PRs through the GitHub's web interface.
See here for more information
https://github.com/blog/2111-issue-and-pull-request-templates



It links to the wiki page about submission rules.

Signed-off-by: Alberto Bursi <alberto.bursi@outlook.it>

Signed-off-by: Ted Hess <thess@kitschensync.net>