Change ILoggerFactory internal lifetime to scoped

[ajcvickers]

This has the following advantages:

• It eliminates internal service provider explosion when calling UseLoggerFactory with a new instance each time. This is currently a significant pit of failure that has consumed many victims.
• This also means that the testing pattern of multiple external service provides (e.g. one per test) does not cause the internal cache to explode.
• It allows a simple implementation for simple logging APIs, since each context instance can naturally have its own logger if desired.

The disadvantages are:

• Internal singleton services cannot depend directly on a logger from D.I. This means either:
  • Making the service scoped
  • Flowing in the logger from a scoped service, which in turn may require breaking changes to add new logging