Define the formulation for the heat markers

- set threshold to 7 default for all locations
- 7 is derived from 2 big org x 3 + 1 for small org.
- if new org comes we need to update the threshold
- Below is the main formula for necessity calculation over 10 - change 10 to 5 to get the rate over 5

- `heatRank = roundUp((1 - ((confirmed volunteers in location.id) / (threshold x (ballot_boxes count in location.id)))) * 10)`

- To include the OvO data we can use the weighted average method and the total calculation is below:
- `ovoAverage = volunteer_counts.priority (for ovo) in location_id / count(buildings in volunteer_counts)`
- `finalRank = roundUp((3/7 * ovoAverage) + (4/7 * heatRank))`