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/coreruleset/drupal_test.go

@@ -9,7 +9,7 @@ import (
 	"sneak.berlin/go/smallwebwaf/internal/coreruleset"
 )
 
-// drupalThreshold is SWW_WAF_CORE_RULE_SET_ANOMALY_THRESHOLD's default.
+// drupalThreshold is SWW_WAF_CORE_RULE_SET_SCORE_THRESHOLD's default.
 const drupalThreshold = 5
 
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