Keep main Apache software license intact and mention the modelDB and Zenodo in the examples directory

[anilbey]

This is mentioned by the AEiC of JOSS
openjournals/joss-reviews#7026 (comment)

BlueCelluLab does not depend on any of those licensed morphology or MOD files to be installed and run.

The MOD and morphologies are not even part of the package resources.
https://github.com/BlueBrain/BlueCelluLab/blob/fe4baed5db1cd3df85012e22e3625fb0646c5b5b/MANIFEST.in

Only the example directories and test directories show its applicability using those files.

So I suggest this commit can be reverted so that the software will have the original Apache license text
baebfcb

And then 2 LICENSE files can be created inside the /examples and /tests to acknowledge where the test and examples data/code (morph and MOD) comes from.

[ilkilic]

addressed in #208