Unify documentation and style files into one product

I am told that the primary documentation for getting PFS accounts is in the Subaru-PFS/doc product, specifically pfs.ipmu.jp/usage.tex. That requires pfsstyle.sty, which is in the Subaru-PFS/pfs_misc product.

I realize that there will be a web page with the formatted PDF, but I suggest that the basic requirements for building docs should be in a/the docs product.