Allow log level to be overridden per file

[apiology]

Useful for debug-level logging being turned on selectively at dev time

The idea here is that we could have code like this:

class SomeRandomClass
  def important_method
    data = logic
    logger.debug { "something happened: #{data}" }
    logic
  end
  
  include Logging
end

We can selectively turn on those debugging lines at dev time by temporarily adding a log_level method:

class SomeRandomClass

  def log_level
    :debug
  end
  
  def important_method
    data = logic
    logger.debug { "something happened: #{data}" }
    logic
  end
  
  include Logging
end

As a result, only the debug lines we care about are brought in while debugging something that interacts with SomeRandomClass

[apiology]

Can we cache this as @logger here?