Add simple saving class

Closes #124 (closed)

Allows daiquiri to configure saving without bliss.

Can be enabled with saving_type: simple in app.yml

basic config:

saving_arguments:
    base_path: "/data/{meta_beamline}/tmp/{sessionid.proposal}"
    template: "{sampleid.name}"
    data_filename: "{sampleid.name}_{datacollectionid}"

• add documentation