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.

Using a config file is not necessary and may be confusing.
Also add address and phone number of User and Branch structs.

Since request.Body can only be read once, calling patchUser from
patchSelf always returned an error. request.Body needed to be either be
saved in a variable and reset or have a new function created.

Uses gift package for server side resizing of selected letterhead
file. It should fit an image file with aspect ratio of 2:1 and be a
reasonable size. A 400x200 resizeToFit is used for now.
gift just uses the native image/draw package internally.
https://pkg.go.dev/image/draw

Estimate creation process  will be more clear if the details entered by
the user is in a seperate page from the summary information shown before
PDF generation. It will also help keep the app looking minimal.

Null makes missing values harder to convert to json using the Scan
operation. 0 and '' will be used instead to be type consistent.

Setup structs for storing query information.