Split comparison, summary, and header sections into seperate files to
reuse headers more easily and make future changes easier.

Move Result attribute from Estimate to it's related Loan to make it's
meaning less confusing.

the htmltopdf.js library renders all PDF text as images instead of
vectors, and Go does not have a reliable native library for generating
PDFs that is actively maintained. The best solution appears to be to
make a system call to wkhtmltopdf, but now there is a hidden package
dependency that is not checked at build time and exists in another
process. Maybe in the future a C library can be used and linked with the
Go binary.