Port to .NET Core

[ForNeVeR]

Prerequisites

• Drop Component-based stuff #2: Drop Component-based stuff
• Remove Form support from CertificatePrompt #4: Remove Form support from CertificatePrompt
• Drop System.ComponentModel.ISynchronizeInvoke  #5: Drop System.ComponentModel.ISynchronizeInvoke
• Remove binary files from the repository #14: Remove binary files from the repository
• Build system changes #15: Build system changes
• Project reorganization #17: Project reorganization
• .NET Core-based build system #61: .NET Core-based build system
• Use alternative mock library in tests #7: Use alternative mock library in tests
• Migrate to .NET Core-compatible XML API #3: Migrate to .NET Core-compatible XML API
• .NET Core-compatible zlib.net replacement #60: .NET Core-compatible zlib.net replacement