feat: dotnet 8 & 10, drop netstandard support and add AddMongoDbContext for Aspire

[glucaci]

This pull request introduces a major upgrade of the codebase to support .NET 10, modernizes build and packaging infrastructure, and simplifies project configuration. The most significant changes are the adoption of .NET 10 across all projects, improved CI/CD workflows, centralization of build properties, and enhanced dependency management.

.NET 10 upgrade and multi-targeting:

• Updated global.json to use .NET SDK 10.0.103, and all projects now target .NET 10 alongside .NET 8 where applicable. This enables development and testing on the latest .NET platform. [1] [2] [3] [4]
• Removed individual TargetFrameworks and IsPackable properties from sample and test projects, delegating these settings to the centralized Directory.Build.props. [1] [2] [3] [4] [5] [6] [7]

Build and packaging infrastructure:

• Added all.csproj using Microsoft.Build.Traversal to simplify building and testing all projects and tests in the repository.
• Centralized build properties and warnings configuration in the renamed Directory.Build.props, including multi-targeting, nullable handling, and packaging metadata.
• Removed legacy property and target files (src/Dependencies.props, src/Directory.Build.targets) and simplified src/Directory.Build.props to use the new centralized approach. [1] [2]R1, [3]

CI/CD workflow modernization:

• Replaced and improved GitHub Actions workflows: introduced a new ci.yml for matrix testing on .NET 10, updated release.yml for modern build, pack, and push steps, and removed the old pull-request.yml. [1] [2] [3] [4]
• Updated workflow actions to the latest versions and improved concurrency and run-naming for better traceability. [1] [2]

Dependency management enhancements:

• Updated package references for .NET 8 and .NET 10, including version ranges and new dependencies (Microsoft.Extensions.Options.ConfigurationExtensions). [1] [2]
• Upgraded Microsoft.SourceLink.GitHub to version 10.0.102 for improved source linking support.

Codebase improvements and new features:

• Added ServiceCollectionExtensions in src/Context for simplified DI registration of MongoDB contexts, supporting configuration binding and connection string handling.
• Set IsPackable to true for main library projects to enable NuGet package creation. [1] [2]
• Removed .config/dotnet-tools.json as SonarScanner tool configuration is no longer needed.

These changes collectively modernize the repository, streamline development and release processes, and ensure compatibility with the latest .NET standards.