Improve grouping of classification decisions

[hudson-newey]

At the moment, users have to explicitly create a verified='true', verified='false', verified='skip', etc... oe-classification button element for every possible verified state.

Instead, we should make it so that adding a oe-classification tag="cow" implicitly adds state modifiers/buttons for all decision states in the decision enum.

We should group classification decisions that target the same tag together in the DOM, perhaps vertically aligning each decision button that modifies the same tag (if there are multiple tags).

Some other ideas to address this problem include:

• A "switch" that has three states positive (up), skip (middle/unmodified), negative (down)
  • Does not address how "unsure" decision would be made, and does not extend well if we want to expand the decision options enum in the future
• Implicitly add four buttons for each enum state
  • Can get very cluttered very fast

[atruskie]

This is how we make better UI, the semantics for this can be found in #135