Tweaks and fixes throughout the project (#27)

This PR contains the work done to do a little bit of housekeeping pass across all packages and the Website service.

To provide further details about the work:
* Refreshed the READMEs and source documentation to match the current code;
* Tagged every test case consistently across the Infrastructure, Localization, Persistence, and Website test targets;
* Removed Website middleware tests now covered by Infrastructure's own suite;
* Conformed the `PrepareDB` method to Sendable;
* Relaxes the production Compose DATABASE_TLS default from require to prefer;
* Added Persistence test verifying the prefer posture falls back to plaintext connections.

Reviewed-on: rock-n-code/loud-amsterdam#27
Co-authored-by: Javier Cicchelli <javier@rock-n-code.com>
Co-committed-by: Javier Cicchelli <javier@rock-n-code.com>

Packages/Persistence/Package.swift

@@ -32,6 +32,14 @@ let package = Package(
             url: "https://github.com/vapor/sql-kit.git",
             from: "3.36.0"
         ),
+        .package(
+            url: "https://github.com/vapor/mysql-nio.git",
+            from: "1.7.0"
+        ),
+        .package(
+            url: "https://github.com/apple/swift-nio.git",
+            from: "2.65.0"
+        ),
     ],
     targets: [
         .target(
@@ -59,7 +67,19 @@ let package = Package(
         .testTarget(
             name: "PersistenceTests",
             dependencies: [
-                .byName(name: "Persistence")
+                .byName(name: "Persistence"),
+                .product(
+                    name: "MySQLNIO",
+                    package: "mysql-nio"
+                ),
+                .product(
+                    name: "NIOCore",
+                    package: "swift-nio"
+                ),
+                .product(
+                    name: "NIOPosix",
+                    package: "swift-nio"
+                ),
             ],
             path: "Tests"
         ),