Add multiband support and shredder support

[esheldon]

• Adapt to use new wavg code for moments
• Add multiband support for the case of not deblending
• Refactor lsst code into a sub package
• Add support for the Shredder
• Add photometry module, same but without doing metacal steps

[esheldon]

I also added a new bit of code to re-find the center rather than trusting the DM center