feat: http provider signing key addition (#10641)

# Which Problems Are Solved

HTTP Request to HTTP providers for Email or SMS are not signed.

# How the Problems Are Solved

Add a Signing Key to the HTTP Provider resources, which is then used to
generate a header to sign the payload.

# Additional Changes

Additional tests for query side of the SMTP provider.

# Additional Context

Closes #10067

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Co-authored-by: Marco A. <marco@zitadel.com>
(cherry picked from commit 8909b9a2a6)

cmd/setup/62.sql

@@ -0,0 +1,2 @@
+ALTER TABLE IF EXISTS projections.sms_configs3_http ADD COLUMN IF NOT EXISTS signing_key TEXT NULL;
+ALTER TABLE IF EXISTS projections.smtp_configs5_http ADD COLUMN IF NOT EXISTS signing_key TEXT NULL;