[WIP] created identify_target function

[simontorres]

The goal of this pull request is to implement a function to identify the location of the spectrum of a point source in a 2D image.

[simontorres]

the initial commit does not contain much code since pyastro19 has arrive to an end and I decided to put the PR already. Here is a document that describes what I'm going to implement. https://github.com/simontorres/general_documentation/blob/master/target_identification/target_identification_test.ipynb

[jehturner]

Is this of interest? I realize it may be a bit tied to our own data access class.

https://github.com/GeminiDRSoftware/DRAGONS/blob/spectroscopy/gempy/library/tracing.py

[stscicrawford]

@jehturner That does look very helpful and has many of the underlying features that would be needed.