Improve Informer and estimator parameter setting

[raphaelshirley]

We are currently setting config parameters in the Python code directly. These should be ceci.config.StageParameter objects with dictionaries that can be set during the inform stage.

We will still load the shared configs from the lsst.para file but all params that differ between stars, galaxies, and quasars should be set during inform.

[raphaelshirley]

This was partly addressed by PR 10 but might be improved if we manage to ensure all features can be captured in a single para file.

#10

[raphaelshirley]

This is all handled though lephare config parameters so closing as is.