Improve module structure

[jacob720]

Fixes #134

Splits converters and models into their own modules based on the type of config file they deal with. Also adds a public API so that all models can be imported with from daq_config_server.models import SomeModel

[olliesilvester]

Thanks, the structure is nicer here. We just need to make sure we're consistent with making private classes/modules and exposing the right bits in the __init__.pys. Ophyd-async is a good example of how it should look, eg see https://github.com/bluesky/ophyd-async/blob/main/src/ophyd_async/epics/adcore/__init__.py

[olliesilvester]

Looks much neater thanks, just a couple of things, but feel free to disagree

[olliesilvester]

Might have missed something but I don't think we need to exposeparse_lut - I think we only use it in the tests right? I think tests should be able to import from private modules, we can probably add a typing rule so that files in the test folder can do this

[jacob720]

That's a good point, I'll remove it

[olliesilvester]

Not relevant to this PR really but can we add a comment just to say it should be the parent class to all other config models

[olliesilvester]

Thanks, looks neat