refactor: update dependencies and remove unused code

- Added new dependencies: `adler2`, `crc32fast`, `flate2`, `miniz_oxide`, and `libredox`.
- Updated existing dependencies: `tokio-rustls` to version 0.26.4 and `filetime` to version 0.2.27.
- Removed the `backup.rs` file as it is no longer needed.
- Introduced tests for configuration and credential management.
- Enhanced the `identity` module to generate W3C compliant DID documents.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

core/security/Cargo.toml

@@ -12,8 +12,10 @@ log = "0.4"
 tracing = "0.1"
 uuid = { version = "1.0", features = ["v4"] }
 chrono = { version = "0.4", features = ["serde"] }
+serde_json = "1.0"
 aes-gcm = "0.10"
 rand = "0.8"
+hex = "0.4"
 
 [dev-dependencies]
 tempfile = "3"