Create or Edit Action - select Carbon Calculator Action using Category and Subcategory

[BradHN1]

User Story.
As a Community Admin
I want to more easily find and select the carbon calculator action associated with a community action
So that I don't need to search through a long un-ordered list

Additional details/context
API PR 840 (ready for final testing and deployment) implements carbon calculator action categories and subcategories. The purpose of these is to make it easier to select actions and enforce consistency between categories of community actions and calculator actions, which are the underlying basis of community acctions. We have added many new cc actions, so the list got a lot longer so it would be more challenging for the community admin to find ansd select the correct one.

In the admin portal edit action page, where the carbon calculator action is created we want to implement a two step process:

1. first you choose the cc action category (one of 7 or so)
2. that opens up the list of subcategories for that category.
3. Choose a subcategory, and that gives the list of cc actions in that subcategory.

Ideally, if a category and subcategory aren't selected you could still look through that long list, pick a CC Action.

in the branch CC-updates, the intern Emma implemented part of this but it need better front-end work to make it right.

Value added.
What do you think the value of adding this feature is? Help managers and developers know how this should be prioritized.

Acceptance criteria.
The conditions that must be met for this to be done. For example, for a login feature: User is securely and reliably logged in until timeout or manual sign-out.

[apowelka]

all lists and drop-downs for categories, sub-cat and actions need to be alphabetical (A-Z)

[apowelka]

adding a search field that leads to a result displaying category - subcategory - action will also be really helpful