Rename the settings whose names do not say what they control (closes #234)

Applies the setting renames of the naming audit under the SWW_WAF_ and
SWW_RPROXY_ prefixes, with sneak's names for the IP reputation cache
time and the two time limits, which now take milliseconds. The rproxy
log field default_disposition becomes waf_backend_no_answer, and
config.Config and config.FromEnvironment become config.WAF and
config.WAFFromEnvironment. Go fields, test names and prose follow. No
aliases; nothing reads the old names.

Model: opus-5-5

internal/sww/rproxy.go

@@ -15,7 +15,8 @@ import (
 
 // RunRProxy is `sww rproxy`: it reads rproxy's settings, then serves
 // requests until ctx is done. Then it gives the requests in progress
-// shutdownTimeout to finish, and the reports being sent SWW_RPROXY_TIMEOUT_MS. It
+// shutdownTimeout to finish, and the reports being sent
+// SWW_RPROXY_WAF_BACKEND_TIMEOUT_MS. It
 // returns the process's exit status, 1 when rproxy cannot start. Its process
 // messages name the host's name as instance, and it writes those at info or
 // more severe: rproxy has no setting for either.