Fix aperture estimation, use local bkg from an annulus for aperture photometry, add the web interface to explore the end results

[juanep97]

This PR:

• Adds an utility function to estimate an appropriate common aperture for a list of reduced fits (it fits the target source profile in the fields and returns some multiples of the fwhm which are used as the aperture and as the inner and outer radius of the annulus for local bkg estimation).
• Changes the way that the bkg is estimated for aperture photometry (before it used a 2d bkg image, now it uses this annulus).
• Remove permission management from the model admins. In production, permissions should be managed using users and groups. While debugging or using the default iop4site, only one user (the superuser) exists and already has all permissions.
• Adds a web interface to explore the end results (in the default iop4site).

[morcuended]

I did a quick review and left some minor comments. Overall is not easy to review the changes without tests. The last test was running forever so I could not fully check it. Anyway, go ahead with the merge

[morcuended]

already imported at the beginning of the file

[morcuended]

remove all the extra blank lines (or better run black formatter)

[juanep97]

This versions passes all tests in both Ubuntu and macOS, and is working for the VHEGA site. I merge if you don't oppose. Sorry for the Monster PR... but it is growing only bigger.

Applying the black or any other formatter will destroy git history. I'm looking what's the best way to deal with it, any idea? I think it can be postponed anyway.

[morcuended]

Go ahead with the merging. Formatting is another matter