Merge IN feeds to a single one

[sumeshpremraj]

This is to address @1Maxnet1's comment in this PR.

This feed is already available in in-ka.json so we should not duplicate it here. I would propose to Either drop the regional files completely and merge their entries into the in.json or we keep this file for nation-wide feeds only and sort the regional feeds into the according files.

Originally posted by @1Maxnet1 in #2145

I can work on this, posted this here for visibility and suggestions/need to address any edge cases.

[jbruechert]

Merging all of the files also means that every current maintainer will receive error reports for each of the contained feeds. Usually it's better to split these if possible too keep them manageable.

[Lach-anonym]

I also think India feeds have potential for growth, so it's good to have them grouped by states for order

[1Maxnet1]

I agree that we can keep the separated files as they currently are. Then #2145 needs to be adapted accordingly.