An empty avatar caused a request for the default icon to be fetched,
which caused the request for the user's letterhead to not be made.

Update the database tables for user and branch to give more information
required for PDF generation. Also set up a test component to preview
change to the view during development. It will be reconfigured once the
genrated PDF is satisfactory.

vue-html2pdf appears unmaintained and hacky so it's being avoided.

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.

Also change the favicon to better match the colorscheme. An additional
section is added to settings.vue to mock the new fields.