Standardize API for logging images, histograms, etc.
🚀 Feature
Standardized way to log non-scalar data
Motivation
Different logging backends supported by PL use different ways to log such data, so it would be very convenient to have standardized way to do it. I mentioned it in Slack and got approval to make a PR, so I want to discuss details here.
Pitch
Add methods that allow to log images, histograms or other data (audio, video, ...) to PL logger class.
Additional context
What is better?
If the function is called, but current logger backend doesn't support this type of content:

silently ignore: we misleading the user allowing him to use method that does nothing without any notification
throw an error: it can be undesired behavior if LoggerCollection is used
show a warning: IMO best solution

What signature should methods have?

log_images(images: Dict[str, image_types]): consistent with existing log_metrics, but new method should be added for each type of data (log_images, log_histograms, ...); IMO best solution
log_image(tag, image): consistent with Tensorboard, but can be inconvenient when logging multiple images
log_metrics where image wrapper is passed as value: consistent with WandB (uses its own wandb.Image wrapper), but requires user to create wrappers and increases complexity

I am ready to make PR when details are discussed and approved.