Remove InternalDebugger

[carmocca]

Proposed refactoring or deprecation

See title

Motivation

The InternalDebugger is legacy and lets us to write bad code. The code should be structured in a way that enables testing.

Pitch

• remove calls to internal dev debugger in training- and eval loop #9188
• remove checkpoint tracking from internal debugger #9326
• remove early stopping tracking from internal debugger #9327
• Remove InternalDebugger.track_lr_schedulers_update #9653
• Remove InternalDebugger.track_event #9654
• remove InternalDebugger.track_load_dataloader_call #9675
• remove InternalDebugger #9680

Additional context

Discussed in #8895

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[awaelchli]

Thanks @carmocca
I have a branch where I started the dataloader removal a while ago.
Have you already started? This one is going to be a bit of effort. Saved it for last.

[carmocca]

No, I haven't. Up for grabs.