This addresses all the comments by @ctlong.
It fixes the unneded if else branching for adding to the message
batch which is just not needed anymore.
It fixes the egressMetric to behave similar to the single message
implementation, to not count erroneous logs.

The refactor is mainly reshuffeling

The new timer implementation makes it more clear what the actual logic
is, and might also prevent some unresolvable states.
It now only has two states:
- Running if a batch is not yet full or time triggered
- Not running if there was a batch send either through a time or a size
based trigger

This is a new approach to switch between http and http batching.
It only is different in this regard from the previous attempts,
and only contains refactorings besides this change.