Use Babel to transpile icons into separate chunks and source maps - No bundling required

Description

The icons are now directly transpiled using Babel and generated into their own individual chunks with source maps. They are no longer bundled using Rollup.
Automatically generate type definitions during build time.
Deleted the Rollup configuration and removed all the dependencies related to bundling.
Build time: 14s => 6s.
NeetoCal: NeetoIcons chunk size reduced from 1.05MB to 625.36KB.
https://github.com/bigbinary/neeto-commons-frontend/pull/1203 shall ensure that all the imports are transformed into the new format.
Explanation: https://abhay-ashokan.neetorecord.com/watch/59b4cae6-166b-44a7-a980-13f65cf143db

Checklist

[x] ~I have made corresponding changes to the documentation.~
[x] I have updated the types definition of modified exports.
[x] I have verified the functionality in some of the neeto web-apps.
[x] I have added the necessary label (patch/minor/major - If package publish is required).

Reviewers

@AbhayVAshokan _a minor _t

bigbinary / neeto-icons