feat: Add environment variable support for DID registration

- Bash implementation of DID creation-registration
- Move admin credentials to .env file for better security
- Add .env.example with default values
- Add dotenv support to TypeScript, Python and Bash implementations
- Update dependencies to include dotenv packages
- Fix JWT signature format in Bash implementation
- Add DER signature parsing for ES256K in Bash script

The admin DID and private key can now be configured via environment
variables, with fallback to default values if not set. This allows
for easier testing and deployment across different environments.

test-scripts/did_generator.py

@@ -22,6 +22,8 @@ Dependencies:
     base64: For JWT encoding
     argparse: For command-line argument parsing
     pathlib: For path handling
+    dotenv: For environment variable loading
+    os: For environment variable access
 
 Usage:
     python did_generator.py [options]
@@ -46,6 +48,11 @@ import argparse
 import secrets
 import hashlib
 from pathlib import Path
+from dotenv import load_dotenv
+import os
+
+# Load environment variables
+load_dotenv()
 
 class DIDRegistration:
     """
@@ -305,12 +312,14 @@ def main():
     parser.add_argument(
         '--api-url',
         help='Override API URL',
-        default="https://test-api.endorser.ch/api/v2/claim"
+        default=os.getenv('ENDORSER_API_URL', 'https://test-api.endorser.ch/api/v2/claim')
     )
     args = parser.parse_args()
-    admin_keypair = { 
-        'did': 'did:ethr:0x0000694B58C2cC69658993A90D3840C560f2F51F', 
-        'private_key': '2b6472c026ec2aa2c4235c994a63868fc9212d18b58f6cbfe861b52e71330f5b' 
+
+    # Get admin credentials from environment
+    admin_keypair = {
+        'did': os.getenv('ADMIN_DID', 'did:ethr:0x0000694B58C2cC69658993A90D3840C560f2F51F'),
+        'private_key': os.getenv('ADMIN_PRIVATE_KEY', '2b6472c026ec2aa2c4235c994a63868fc9212d18b58f6cbfe861b52e71330f5b')
     }
 
     admin_did = args.admin_did