Add Cumulative Score "steps" section to methodology page (#489)

* Step progress list
* Layout mostly done. Need to do intl() conversion but it's easier to understand the layout like this.
Will do intl in a different PR
* fix: `em` to `rem`
* Add basic snapshot unit test

client/src/components/scoreStepsList.tsx

@@ -0,0 +1,88 @@
+import React from 'react';
+import {GridContainer, Grid} from '@trussworks/react-uswds';
+
+const ScoreStepsList = () => {
+  return (<>
+    <div className={'j40-process-list-wrapper'}>
+      <ul>
+        <li>
+          <section>
+            <h3 className={'j40-item-list-title'}>Gather datasets</h3>
+            <p><h4 className={'j40-item-list-subtitle'}>Data inputs</h4>
+              The cumulative index score includes the following equally
+              weighted inputs.
+              <ul>
+                <li>Poverty</li>
+                <li>Less than high school education</li>
+                <li>Linguistic isolation</li>
+                <li>Unemployment rate</li>
+                <li>Housing burden</li>
+              </ul>
+            </p>
+            <p>
+              <h4 className={'j40-item-list-subtitle'}>
+                Combining data from different geographic units</h4>
+                Some data is not available at the census block group level and is
+                instead only available for larger units such as census tracts or
+                counties. In these cases, all census block groups will get an even
+                contribution from the larger unit. For example, if a census tract
+                scores 90th percentile on an indicator, then all census block
+                groups within that tract will receive a value of 90th percentile.
+            </p>
+            <p><h4 className={'j40-item-list-subtitle'}>Normalizing data</h4>
+                The range of the data that makes up the score varies, so the data
+                must be normalized so that each data indicator can be more equally
+                weighted. Min-max normalization is utilized, where the minimum
+                value in the range of values for each dataset is set at 0, the
+                maximum value is set at 1, and every other value is transformed
+                into a decimal between 0 and 1. For example, if the minimum value
+                for unemployment was 10 and the maximum value was 30, a value of
+                20 would be transformed to 0.5 since it is halfway between 10 and
+                30.
+            </p>
+          </section>
+        </li>
+
+        <li>
+          <section>
+            <h3>Calculate cumulative index score</h3>
+            <p>To combine all variables into a single cumulative index score,
+                we average the normalized values across indicators.
+            </p>
+            <p>
+              <GridContainer className={''}>
+                <Grid row className={'j40-math-division-container'}>
+                  <Grid col className={'j40-math-eq-left-side grid-col-fill'}>
+                    <div className={'j40-math-eq-numerator'}>
+                Dataset 1 + Dataset 2 + ... + Dataset N
+                    </div>
+                    <div className={'j40-math-eq-denominator'}>
+                # of datasets
+                    </div>
+                  </Grid>
+                  <Grid col className={'j40-math-eq-middle grid-col-auto'}>=</Grid>
+                  <Grid col className={'j40-math-eq-right-side grid-col-fill'}>Cumulative index score</Grid>
+                </Grid>
+              </GridContainer>
+            </p>
+          </section>
+        </li>
+
+        <li>
+          <section>
+            <h3 className={'j40-item-list-title'}>Assign priority</h3>
+            <p>
+                Census block groups are sorted by their cumulative index score
+                from highest to lowest. Census block groups that are in the top 25
+                percentile (i.e. have a cumulative index score in the 75 - 100th
+                percentile) will be considered the prioritized communities.
+            </p>
+          </section>
+        </li>
+      </ul>
+    </div>
+  </>
+  );
+};
+
+export default ScoreStepsList;