chore(oidc): graduate webkey to stable (#10122)

# Which Problems Are Solved

Stabilize the usage of webkeys.

# How the Problems Are Solved

- Remove all legacy signing key code from the OIDC API
- Remove the webkey feature flag from proto
- Remove the webkey feature flag from console
- Cleanup documentation

# Additional Changes

- Resolved some canonical header linter errors in OIDC
- Use the constant for `projections.lock` in the saml package.

# Additional Context

- Closes #10029
- After #10105
- After #10061

internal/crypto/rsa.go

@@ -21,14 +21,6 @@ func GenerateKeyPair(bits int) (*rsa.PrivateKey, *rsa.PublicKey, error) {
 	return privkey, &privkey.PublicKey, nil
 }
 
-func GenerateEncryptedKeyPair(bits int, alg EncryptionAlgorithm) (*CryptoValue, *CryptoValue, error) {
-	privateKey, publicKey, err := GenerateKeyPair(bits)
-	if err != nil {
-		return nil, nil, err
-	}
-	return EncryptKeys(privateKey, publicKey, alg)
-}
-
 type CertificateInformations struct {
 	SerialNumber *big.Int
 	Organisation []string