Add configuration type binding and implement database connection, disable NativeAOT.

Add: binding setting file items to `AppSettings` class so to provide DI access as `IOptions<OptixServeSettings>`.

Add: EF Core and DbContext to access database in services. This results in disabling NativeAOT due to poor supports for *pre-compiled query*, however many design are optimized for AOT for later re-adoption.

Add: `DesignTimeDbContextFactory` to support EF Core migrations in NativeAOT. (Kept for re-enabling AOT.)

Add: `DbInitializer` for ensuring database connecting in startup.

Add: `ConfigurationHelper.CreateDefaultBuilder()` to read configuration files in default locations. Note this method is currently ONLY used by `DesignTimeDbContextFactory`. Refactor is expected.

Add: `CommonErrorDto` for simple error message.

Add: `VersionEndpoint` ONLY for debugging and testing purpose. Verylikely to be removed in the future.

Other: many utilities and fixes easy to understand.

Note: EF Core migrations are excluded in the early development. Not expected to be added in version control before v1.0 beta.

OptixServe.Api/Dtos/Error.cs

@@ -0,0 +1,6 @@
+namespace OptixServe.Api.Dtos;
+
+public record CommonErrorDto
+{
+    public string? Message { get; set; }
+}