Add SigNoz access review driver

Add a SigNoz connector so its organization members can be pulled into
access-review campaign snapshots. SigNoz authenticates with a
SIGNOZ-API-KEY admin service-account key and a customer-supplied base
URL (a SigNoz Cloud region/tenant host or a self-hosted instance).

The driver lists users via GET /api/v1/user, which returns the role
(ADMIN/EDITOR/VIEWER) inline so admin detection works in a single call,
and maps the SigNoz user status (active / pending_invite / deleted) to
the account active flag. The name resolver reads the organization
display name from GET /api/v2/orgs/me to title the access source.

Wire the provider through the coredata enum and settings, the
connector-provider registry (driver and name-resolver factories), the
console API-key input schema and validation, the access-review source
label, and the SigNoz brand logo.

Co-authored-by: Bryan FRIMIN <bryan@frimin.fr>
Signed-off-by: Aurélien Sibiril <81782+aureliensibiril@users.noreply.github.com>

pkg/accessreview/drivers/vcr_test.go

@@ -51,10 +51,12 @@ func newRecorder(t *testing.T, cassettePath string, envVar string) *recorder.Rec
 		)),
 		recorder.WithHook(func(i *cassette.Interaction) error {
 			i.Request.Headers.Del("Authorization")
-			// Providers like Anthropic authenticate via x-api-key rather
-			// than Authorization; strip it too so a re-record never
+			// Providers like Anthropic (x-api-key) and SigNoz
+			// (SIGNOZ-API-KEY) authenticate via a custom header rather
+			// than Authorization; strip those too so a re-record never
 			// persists a raw key.
 			i.Request.Headers.Del("X-Api-Key")
+			i.Request.Headers.Del("Signoz-Api-Key")
 
 			return nil
 		}, recorder.BeforeSaveHook),