internal/config now keeps waf's settings in waf.go and rproxy's in
rproxy.go. config.go keeps what both read: the package doc,
SWW_COMMAND, the environment reader, listen addresses, sizes and
netblock lists. The app URL reader and the default trusted proxies,
which only rproxy uses, move to rproxy.go. config_test.go becomes
waf_test.go, beside rproxy_test.go. Code is moved, not changed.
Model: opus-5-5
sneak