Use InterpolatedStringHandler for `ZLog`

[hadashiA]

Significant changes to ZLog signatures.

• Before: ZLog<T1, T2, ...>
  • Avoid boxing allocations via generics method family.
• After ZLog(..., ref ZLoggerInterpolatedStringHandler)
  • Using [InterpolatedStringHandler] and parsing of the format string is completed at compile time.
  • Note: avoid boxing allocation is a later todo.Allocation is a TODO.

Chanegs in this PR

• Add ZLoggerInterpolatedStringHandler, and new ZLog(...) methods.
• Use new IZLoggerFormattable interface from ILogger.
• Replace IZLoggerEntry to new ZLoggerEntry<TState> way.
• Replace IZLoggerFormatter implementations to new way of using IZLoggerFormattable.
• Replace ZString to Utf8StringInterpolation.