Add draft ADR on S3 object definition (#177)

Adds ADR on S3 object definition.

Co-authored-by: Sebastian Bernauer <sebastian.bernauer@stackable.de>
Co-authored-by: Razvan-Daniel Mihai <84674+razvan@users.noreply.github.com>
Co-authored-by: Lars Francke <github@lars-francke.de>

Author: 4 people

modules/contributor/images/adr/s3-object-bucket-claim.png

@@ -13,6 +13,7 @@
 **** xref:adr/ADR012-authn_token_management.adoc[]
 **** xref:adr/ADR013-user_authentication_for_products.adoc[]
 **** xref:adr/ARD014-using_values_from_configmaps.adoc[]
+**** xref:adr/ADR015_definition_of_s3_objects.adoc[]
 *
 *** Deprecated
 **** xref:adr/deprecated/ADR006-choose_orchestrator_storage_backend.adoc[]