Allow renaming keys added by CallsiteParameterAdder

[Cnoor0171]

Currently, CallsiteParameterAdder always adds each parameter under a predetermined key. It would be nice if the user can specify an alternate key for each parameter instead.

A pretty simple to implement and fully backwards compatible way would be to change the init method from

    def __init__(
        self,
        parameters: Collection[CallsiteParameter] = _all_parameters,
        additional_ignores: list[str] | None = None,
    ) -> None:

to

    def __init__(
        self,
        parameters: Collection[CallsiteParameter] | Mapping[str, CallsiteParameter] = _all_parameters,
        additional_ignores: list[str] | None = None,
    ) -> None:

The user can then instantiate the processor as

CallsiteParameterAdder({"tid": allsiteParameter.THREAD, "pid": allsiteParameter.PROCESS})

[dhirschfeld]

This would be handy. My use-case is conforming to the field names expected by Elastic:

• https://www.elastic.co/guide/en/ecs-logging/overview/master/intro.html#_field_mapping

My (planned) workaround is to have a renaming processor to do a final mapping of names to the ECS equivalents.