GroupVerify: Verification page, overrides and public Verified tags

Shown only where GroupVerify is: staff get the Verification page once its gv_* tables are in
the database, and the public site shows "Verified" only while it's on (enabled, with a group)
and not missing from css_plugins list, which the poller reads once a minute over RCON.

- Verification page: plugin state and version, Steam group, saved member list, overrides.
- Overrides (@zio/verify, not on yourself unless Root): give, change, remove; player drawer
  shows why a player is or isn't verified.
- Root sets the group and turns it on/off: saved to gv_settings, and sent as css_gv_* when the
  plugin is loaded so it applies at once.
- gv_* times use GroupVerify's own timezone setting.
- MySQL integration test (SAW_TEST_DSN), unit tests for plugin list parsing and the show rule.

internal/web/server.go

@@ -41,6 +41,7 @@ type Server struct {
 	poll    *live.Poller
 	sacfg   *saconfig.File // nil when no config path is set
 	staff   *staffCache
+	verify  *verifyCache
 	avatars *avatarCache
 	http    *http.Client
 	secure  bool
@@ -63,6 +64,7 @@ func New(cfg Config, st *store.Store, rc *rcon.Client, poll *live.Poller, sacfg
 		poll:    poll,
 		sacfg:   sacfg,
 		staff:   &staffCache{st: st, ttl: 15 * time.Second},
+		verify:  &verifyCache{st: st, ttl: 30 * time.Second},
 		avatars: newAvatarCache(&http.Client{Timeout: 10 * time.Second}),
 		http:    &http.Client{Timeout: 10 * time.Second},
 		secure:  u.Scheme == "https",
@@ -101,6 +103,7 @@ func (s *Server) Handler() http.Handler {
 	admin("GET /api/admin/comms", s.adminComms)
 	admin("GET /api/admin/staff", s.adminStaff)
 	admin("GET /api/admin/settings", s.adminSettings)
+	admin("GET /api/admin/verify", s.adminVerify)
 
 	admin("POST /api/admin/penalties", s.addPenalty)
 	admin("POST /api/admin/penalties/lift", s.liftPenalty)
@@ -117,6 +120,9 @@ func (s *Server) Handler() http.Handler {
 	admin("DELETE /api/admin/staff/{steamid}", s.removeStaff)
 	admin("POST /api/admin/settings/cvars", s.saveCvars)
 	admin("POST /api/admin/settings/simpleadmin", s.saveSimpleAdmin)
+	admin("POST /api/admin/verify/overrides", s.setOverride)
+	admin("DELETE /api/admin/verify/overrides/{steamid}", s.removeOverride)
+	admin("POST /api/admin/verify/settings", s.saveVerifySettings)
 
 	return s.headers(mux)
 }