Add CODEOWNERS file (#299)

* Add CODEOWNERS file template

* update CODEOWNERS

---------

Co-authored-by: nethermind-oss-compliance[bot] <189609862+nethermind-oss-compliance[bot]@users.noreply.github.com>
Co-authored-by: julio4 <30329843+julio4@users.noreply.github.com>

Author: nethermind-oss-compliance[bot]

CODEOWNERS

@@ -0,0 +1,16 @@
+# =============================================================================
+# GLOBAL OWNERS
+# =============================================================================
+* @NethermindEth/nubia-admins
+* @NethermindEth/nubia-general
+* @NethermindEth/nubia-starknet-by-example
+* @NethermindEth/nubia-starknet-by-example-admin
+* @NethermindEth/role_angkor_admin
+* @NethermindEth/role_legal_users
+* @NethermindEth/role_nubia_admin
+* @NethermindEth/security-admins
+
+# =============================================================================
+# INDIVIDUALS
+# =============================================================================
+* @julio4