Priorities for goals (#961)

This attempts to add priorities for goal templates and addresses most of
https://github.com/actualbudget/actual/issues/959

.

I couldn't find a good way to preserve both "Apply" and "Overwrite"
operations, so this PR does away with the current "Apply" action
behavior. Every box with a budgeted value will be overwritten if a
template goal is present.

The added syntax to define priorities is as follows:
#template    -- priority 0, highest priority
#template-1  --priority 1, 2nd highest priority
#template-2 --priority 2, 3rd highest priority
#template-N --priority N, as many as you'd like.

~~Leaving as a draft as this may not be the preferred implementation but
I wanted others to be able to try it with netlify.~~

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Co-authored-by: Caleb Young <cwy@rincon.com>