Add ZTF Forced Photometry Service

[jchate6]

As a tom user, I would like a module to define and query forced photometry servers to pull in photometric and spectroscopic data for my targets. Rachel's intern Ezequiel has a tom toolkit project branch with code for accessing atlas, ztf, and and panstarrs forced photometry. They all access in different ways, but I think it would be best to design an interface to handle all of these methods of requesting forced photometry into a tom module, like tom brokers or tom_observations. It seems like you might want to request them from a specific targets detail page, or from its own interface. The forced photometry servers can work synchronously, asynchronously (task queue), and asynchronously with the end result emailed to you, which then requires you to upload data files from that email into your tom.

Modes of operation to support:

• ztf - email you data files that then need to be uploaded
• panstarrs - synchronous gets images from position
• atlas - asynchronous task queue until data is ready

This story is to copy and refactor the code for ztf implementation of forced photometry service

https://github.com/econtrerasmartinez09/myTOM

Tasks:

• Add ztf implementation of tom forced_photometry server
• Create ZTF data processor implementation