International Destination Nodes Are Mapping Hierarchy Agnostic

[ikartik90]

Describe the bug
Countries, and Cities belonging to those countries, are showing up as separate Destination nodes on the Travel Cluster graph.
For example, "California", "Washington" and "New York" are showing up as independent international destination nodes and the country they belong to, i.e., "USA" is showing up as an independent international destination node in itself.

A similar, yet broader issue exists with the United Kingdom. The UK is composed of four countries, namely England, Scotland, Northern Ireland and Wales. While "UK" is showing up as an independent international destination node in itself, there are some nodes on the map that belong to one of the countries within the UK, such as "Birmingham" and "London" are cities in England. Further, "Scotland" which is a country in itself within the UK is showing up as a separate destination node.

To Reproduce
Steps to reproduce the behavior:

1. Go to 'https://www.covid19india.org/clusters'
2. Select 'Travel' cluster filter
3. You would notice separate travel nodes for "New York", "Washington", "California" while "USA" exists as an independent international destination node.

Expected behavior
The patients should be tagged to the city nodes or to the nearest node representing their travel in the order of City > Country > Union of Countries. The city nodes should be tagged to their respective country nodes which should in turn be tagged to their country union nodes.

For example, patient nodes tagged to Birmingham and London should remain intact, while Birmingham and London should in turn be tagged to England. Further, England and Scotland should in turn be tagged to the UK node.

Screenshots

[sibeshkar]

Would recommend opening one issue large issue referring all these at the NLP repo. #147 (comment)