Methodology page update for Score L (#1010)

* Add first column of Methodology score L

- create a new component MethodologyFormula (MF)
- MF component contain text on formula calculation
- add snapshots

* Add 2nd column to Methodology page

- add LowIncome component
- add USWDS styles on download component
- add margin-top styles to global
- enable all font-sizes to theme file

* Add Categories to Methodology page

- create CategoryCard component
- create Categories component
- add snapshots

* Update datasets

- update styling to match mock
- add additional indicators
- remove additional indicators
- update snapshots

* Add links to categories to datasets

- update snapshots

* Remove additional indicator test as they now N/A

* ensure each DOM ID is unique for a11y

- update snapshots

* Add Category heading for a11y

- removes ScoreSteps tests
- comment out ScoreStep component
- update snapshots
- cypress passes all a11y

* Update to methodology copy

- based on PDF and spreadsheet and Living Copy
-updates snapshots

* Add comments around using IF, AND, ELSE constants

- make indicator constant names more explicit

* Update copy based on living doc

- update snapshots

client/src/components/DatasetCard/datasetCard.module.scss

@@ -1,3 +1,4 @@
+@use '../../styles/design-system.scss' as *;
 @import '../utils.scss';
 
 @mixin baseCard {
@@ -8,7 +9,7 @@
 
 .datasetCard {
   @include baseCard;
-  background-color: white;
+  @include u-bg("gray-3");
 }
 
 .datasetCardAdditional {