Add inputReader for easy reading of edm4hep or lcio files

[Zehvogel]

BEGINRELEASENOTES

• Add inputReader for easy reading of edm4hep or lcio files

ENDRELEASENOTES

see discussion in #178

[tmadlener]

Since we are on the topic of making this "easy to use". Is there an easy way to also deal with the conditional attaching of a converter? From a quick look at the code we would need the algList and attach it to the first MarlinWrapper algorithm? That could also check that the first / only algorithm before that is the PodioInput (or do nothing in case it's an LcioEvent?

Maybe there is something more clever, but I would be happy with a two step/function approach for the moment.

[Zehvogel]

I will add conversion in the other direction in another pr later

[tmadlener]

Apart from a bit of missing documentation I am very happy with this. Thanks :)

[tmadlener]

Can you add a brief description as a docstring that contains the fact that this is pretty much what you want to do if you have used create_reader unconditionally?

[Zehvogel]

done :)

[jmcarcell]

Suggested change

	if (isinstance(alg, MarlinProcessorWrapper)):
	if isinstance(alg, MarlinProcessorWrapper):

[Zehvogel]

thx