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

Every cache of answers from an outside service has its own file in `SWW_CACHE_DIR` (default `/var/cache/sww`): `lookups.json` (GeoJS), `lists.json` (lists fetched by URL, CrowdSec's decisions included), `dnsbl.json`, `abuseipdb-scores.json` and `routewatch.json` (at most 100,000 answers, each kept an hour). `reputation.json` is gone; the AbuseIPDB checks spent today stay in `SWW_STATE_DIR` as `abuseipdb-checks-spent.json`, since losing them would spend the daily budget twice.

A cache file never stops the start: one that does not parse is set aside as `<name>.bad` with a `file_error` alert. An unwritable `SWW_CACHE_DIR` stops the start. The `run` script creates the cache directory and gives it to `sww`. The cache directory needs no volume and can be left out of backups.

Model: opus-5-5

internal/waf/crowdsec_test.go

@@ -16,7 +16,7 @@ import (
 
 // The CrowdSec settings, and the tests' engine, which is never asked: each
 // test puts in the copy of its decision list, at decisionsURL, that it
-// needs, as reputation.json would at start.
+// needs, as lists.json would at start.
 const (
 	crowdSecURL  = "SWW_CROWDSEC_LAPI_URL"
 	crowdSecKey  = "SWW_CROWDSEC_LAPI_KEY"
@@ -182,7 +182,7 @@ func TestObserveModeForwardsAClientTheCrowdSecDecisionListListsAndAlertsTheBan(
 
 // loadDecisions puts into server's lists the copy of the decision list at
 // decisionsURL, answer, the engine's answer, fetched at fetched, as
-// reputation.json would at start.
+// lists.json would at start.
 func loadDecisions(
 	t *testing.T, server *waf.Server, fetched time.Time, answer string,
 ) {