Certificate Service, Certificate Store and Hashing Facilities

[StefanGreve]

TODOS

• use IFileSystem in ICertificateService
• (start to) add libsodium
• create KDFProvider, KDFService (IKDFService)

DevOps / Documentation

• import certificate in test runner (windows)
• import certificate in test runner (ubuntu)
• import certificate in test runner (macos)
• configure different types of certificates for testing purposes
• use --configuration Release for build and test command in Git hooks and GitHub Actions workflows
• implement HMACProvider
• implement HMACService

Documentation

• Add doc strings to ICertificateService
• Add doc strings to IHashService
• Add doc strings to IHMACService

Unit Tests

• test ICertificateService
• test IHashService
• test HMACProvider
• test IHMACService
• Rethink concept of startup validation of pre-configured certificates

Code Quality Checks

• Start to use attributes from https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/attributes/nullable-analysis where appropriate