Add support for From and To method conversions (#1117)

Description

• Added support for conversion by calling the ToTTarget method on the source object
• Added support for conversion by calling the static Create, CreateFrom, FromTSource methods on the integer type, as well as by calling the static ToTTarget method on the source type

Despite the discussion in the issue, the ToString mapping builder remains untouched as it contains a lot of logic.
Instead, the new mapping builder eliminates the mapping to string.

The previously existing mapping builders for DateTime mapping have been removed, as their role is now performed by the new mapping builder for static methods.
However, MappingConversionType has only been extended, the previously existing MappingConversionType.DateTimeToDateOnly and MappingConversionType.DateTimeToTimeOnly are left for backward compatibility, their processing has been moved to the new mapping builder

Fixes #1117

Checklist

• The existing code style is followed
• The commit message follows our guidelines
• Performed a self-review of my code
• Hard-to-understand areas of my code are commented
• The documentation is updated (as applicable)
• Unit tests are added/updated
• Integration tests are added/updated (as applicable, especially if feature/bug depends on roslyn or framework version in use)