treewide: switch crypto lib to WolfSSL (#2509)

WolfSSL has a significant lower flash footprint. Also, issues with OWE /
SAE connections were fixed in OpenWrt a while ago.

See https://github.com/openwrt/openwrt/commit/ddcb970274c011d3db611ec39350ee4704ff0e02



Signed-off-by: David Bauer <mail@david-bauer.net>