Name log fields, metrics and the Core Rule Set package for what they are (closes #192)

Log field, metric, action and event names now say what they count
and, for timings, the unit. Package internal/waf is internal/coreruleset.

Model: opus-5-5

internal/discriminator/admin_test.go

@@ -356,7 +356,7 @@ func adminEndpoints() []adminEndpoint {
 
 // admin sends a request with method for path, with body, to discriminator's own
 // address, with the admin token, and checks that it is answered with status, its
-// log line's action admin. It returns the answer.
+// log line's action own_endpoint. It returns the answer.
 func (s *sender) admin(method, path, body string, status int) answer {
 	s.t.Helper()
 
@@ -380,7 +380,7 @@ func (s *sender) adminRequest(
 
 	line := s.out.endedLines(s.t, s.sent+1)[s.sent]
 	s.sent++
-	wantLine(s.t, line, status, requestlog.ActionAdmin)
+	wantLine(s.t, line, status, requestlog.ActionOwnEndpoint)
 
 	return got
 }