Supporting automation testing

[chriswxyz]

Especially with forms, it's important to allow various E2E test engines to target fields, forms and values by giving attributes on elements that these runners can target.

Suggested implementation is a data-auto attribute following this naming convention:
a-* for actions
v-* for viewable things to check
i-* for inputs
c-* for containers (to find things inside 3p libs)

For example, data-auto="v-datetime" or data-auto="i-${input-name}"