Add support to optional log message prefix

[prodis]

Commonly a prefix is used in log messages.

For example:

[
  "[",
  inspect(__MODULE__),
  "] My info message."
]
|> Miss.String.build()
|> MetaLogger.info()
# => [MyModule] My info message.

My proposal is to create an overload function for each log level to receive the message prefix:

MetaLogger.info("PREFIX", "My info message")
# => [PREFIX] My info message.

MetaLogger.info(__MODULE__, "My info message")
# => [MyModule] My info message.