Caches of outside APIs live in /var/cache/sww (closes #314)

The answers of GeoJS, the lists fetched by URL, the DNS blocklists,
AbuseIPDB and routewatch each go in a cache file in SWW_CACHE_DIR
(default /var/cache/sww): lookups.json, lists.json, dnsbl.json,
abuseipdb-scores.json and routewatch.json. reputation.json is gone. The
AbuseIPDB checks spent today are a count, not a cache, and stay in
SWW_STATE_DIR as abuseipdb-checks-spent.json.

A cache file never stops the start: one that does not parse is set
aside as an edit is, one that cannot be read is written over, and its
cache starts empty. An unwritable SWW_CACHE_DIR stops the start, as an
unwritable SWW_STATE_DIR does. Each directory is watched on its own.
The run script makes the cache directory and gives it to sww.

Model: opus-5-5

internal/reputation/reputation_test.go

@@ -260,7 +260,7 @@ func TestKeptCopyIsFetchedAgainOnceRefreshHasPassedSinceItWasFetched(t *testing.
 		lists.SetTransport(servers)
 
 		// drop.txt was fetched an hour ago, and tor.txt a refresh ago, as
-		// reputation.json says at start.
+		// lists.json says at start.
 		err := lists.Load([]reputation.List{
 			{URL: dropURL, Fetched: time.Now().Add(-time.Hour), Lines: []string{"203.0.113.9"}},
 			{URL: torURL, Fetched: time.Now().Add(-refresh), Lines: []string{"198.51.100.9"}},
@@ -297,7 +297,7 @@ func TestRestartWaitsRefreshAfterTheLastTryEvenOneThatFailed(t *testing.T) {
 		time.Sleep(refresh)
 		wantFetches(t, servers, 2)
 
-		// Restarted with what reputation.json keeps, it waits a refresh
+		// Restarted with what lists.json keeps, it waits a refresh
 		// after the failed try, as it does while it runs.
 		restarted := &standIn{lists: map[string]string{dropURL: "198.51.100.2\n"}}
 		again := reputation.New(params(dropURL))
@@ -353,7 +353,7 @@ func TestFetchCutOffAsItStopsIsNoFailureButARestartWaitsForIt(t *testing.T) {
 				waiting(queue))
 		}
 
-		// Restarted an hour later with what reputation.json keeps, it fetches
+		// Restarted an hour later with what lists.json keeps, it fetches
 		// tor.txt, never tried, at once, and drop.txt a refresh after its
 		// cut-off try.
 		time.Sleep(time.Hour)