Move derived metrics to preprocessing script

[jmelot]

Closes #233

There were 5 "derived" metrics that didn't have ranks. This PR moves these metrics to the pre-processing script where they are assigned ranks. In doing this, I realized we don't display ranks for percentage metrics, so we can come back to that in https://github.com/georgetown-cset/parat/issues/347

[github-actions[bot]]

No need for rebasing :+1: behind_count is 0 ahead_count is 4

[github-actions[bot]]

☂️ Python Coverage

current status: ✅

Overall Coverage

Lines	Covered	Coverage	Threshold	Status
597	395	66%	0%	🟢

New Files

No new covered files...

Modified Files

File	Coverage	Status
web/scripts/retrieve_data.py	60%	🟢
web/tests/test_retrieve_data.py	100%	🟢
TOTAL	80%	🟢

updated for commit: d46bcd0 by action🐍

[github-actions[bot]]

JavaScript Coverage

Summary

Lines	Statements	Branches	Functions
	67.77% (389/574)	57.18% (191/334)	67.93% (125/184)

Modified Files • (67%)

File	% Stmts	% Branch	% Funcs	% Lines	Uncovered Line #s
All files	67.77	57.18	67.93	67.53
static_data	69.64	48.48	77.27	67.3
data.js	100	100	100	100
table_columns.js	68.51	48.48	77.27	66	218–571