poco:add package for the Poco C++ library
POrtable COmponents is a Modern, powerful open source C++ class libraries
for building network- and internet-based applications that run on desktop,
server, mobile and embedded systems.
Original Makefile -->
https://dev.openwrt.org/browser/packages/libs/poco/Makefile
add license
add maintainer
update URL to latest github stable version (1.7.0)
change patch to the configure file
add a patch to build with musl-libc
Signed-off-by: Jean-Michel Julien <jean-michel.julien@trilliantinc.com>