Adds integration test for subpixel matching using CTX observations.

# Global Map

## Major Data Structures

### Network vs. Non-Network

The major data structures: graph, node, and edge have network versions (e.g., `NetworkNode` and `NetworkCandidateGraph`). These inherit all functionality from the non-network versions and add I/O operations that use network resources. Network resources can be processing queues, databases, and remote job submission through job orchestrators like slurm.

It is preferable to implement analytic capabilities in the non-network versions of the data structures. The goal is that the network versions simply retrieve data and push results to non-memory locations.

## Testing

The library is tested via unit and integration tests.

## Sensor Models

Sensor models are abstracted through a common interface. That interface is stored in 

# Gotchas

Here are a number of different gotchas in the library that deal with stuff.

## Latitude: Ocentric vs. Ographic

There are two different ways to define latitude. See [the proj docs](https://proj.org/en/9.4/operations/conversions/geoc.html) for a in-depth description of ocentric vs. ographic latitudes. This library is impacted when working with other libraries that default to a particular latitude definition. As of the 1.2.0 release, all latitudes inside this library are ographic, conforming to the PROJ standard. The CSM (usgscsm) working in XYZ/BCBF coordinates, so anytime one converts those to lat/lons, they use PROJ and have ographic latitudes. The ISIS library defaults to ocentric latitudes. So, passing a lat/lon pair into a program like `campt` assumes that that latitude is ocentric. So, the autocnet.camera.sensor_models `ISISSensor` object takes can of transformations to ocentric when a lat/lon pair is passed. That same object defaults to returning ographic latitudes when one queries for ground coordinates. When writing a control network, one writes the XYZ/BCBF coordinates. Therefore, no conversion has to take place. 

When adding any functionality to the library dealing with sensor models and ISIS either (1) use the `ISISSensor` interface or (2) be very careful to convert to/from ographic/ocentric latitudes as appropriate.

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