Consistent way to make deprecate features

[IvoDD]

Is your feature request related to a problem? Please describe. It's hard to remove unneeded parts of the API. We can add a docstring that it's deprecated but no one will ever notice it.

Describe the solution you'd like We should have a common way of dealing with deprecations. Ideally a function which does the following:

• Warns the user about the method they're using which is deprecated and suggests an alternative.
• Doesn't spam with warnings. E.g. Makes sure the warning is printed only once.
• Inside Man: Publish a prometheus metric about every time a deprecated feature is used. This way we can track down specific people who are using deprecated features and if e.g. no one used a deprecated feature for a month we can confidently remove it.