chore: cleanup and nixify

* create containers with nix
* updated README.md
* added SPDX license headers

Signed-off-by: Harald Hoyer <harald@matterlabs.dev>

assets/Azure-DCAP-Client.patch

@@ -1,38 +0,0 @@
-diff --git a/src/dcap_provider.cpp b/src/dcap_provider.cpp
-index d23c250..34c4d9d 100644
---- a/src/dcap_provider.cpp
-+++ b/src/dcap_provider.cpp
-@@ -1333,7 +1333,7 @@ static std::string build_tcb_info_url(
-         tcb_info_url << base_url;
-     }
-     else
--        tcb_info_url << get_base_url();
-+        tcb_info_url << "https://api.trustedservices.intel.com/sgx/certification";
- 
-     if (!version.empty())
-     {
-@@ -1426,7 +1426,7 @@ static std::string build_enclave_id_url(
-         qe_id_url << base_url;
-     }
-     else
--        qe_id_url << get_base_url();
-+        qe_id_url << "https://api.trustedservices.intel.com/sgx/certification/";
- 
-     // Select the correct issuer header name
-     if (!version.empty())
-@@ -1521,6 +1521,7 @@ static quote3_error_t get_collateral(
-                 "Successfully fetched %s from URL: '%s'.",
-                 friendly_name.c_str(),
-                 url.c_str());
-+/*
-             std::string cache_control;
-             auto get_cache_header_operation = get_unescape_header(*curl_operation, headers::CACHE_CONTROL, &cache_control);
-             retval = convert_to_intel_error(get_cache_header_operation);
-@@ -1534,6 +1535,7 @@ static quote3_error_t get_collateral(
-                     local_cache_add(issuer_chain_cache_name, expiry, issuer_chain.size(), issuer_chain.c_str());
-                 }
-             }
-+*/
-         }
- 
-         return retval;

assets/extract-sig.sh

@@ -1,8 +1,10 @@
 #!/usr/bin/env bash
+#
 # SPDX-License-Identifier: Apache-2.0
+# Copyright (c) 2024 Matter Labs
 #
+
 # This script is used to extract the signature of a gramine docker image.
-#
 # Usage: ./extract-sig.sh <image-name> <tee-name> <output-file>
 # Example: ./extract-sig.sh tva tee-vault-admin
 

assets/replace-sig.sh

@@ -1,8 +1,10 @@
 #!/usr/bin/env bash
+#
 # SPDX-License-Identifier: Apache-2.0
+# Copyright (c) 2024 Matter Labs
 #
+
 # This script is used to replace the signature of a gramine docker image with a new one.
-#
 # Usage: ./replace-sig.sh <image> <new-signature-file> <old-signature-file>
 # Example: ./replace-sig.sh tva tee-vault-admin.sig /app/tee-vault-admin.sig
 

assets/vault-auth-tee.sha256

@@ -1 +0,0 @@
-7e417b65b9a4fa46dfcc72feb0f0c2e5fa4391c3f6b668cb2c5ba7174b95c43b