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.

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