Feature: Added slack tokens and pod name to get token index

[ani1311]

This MR adds two features:

• First is changing token to read a list of comma seperated slack tokens
• Second is to use HOSTNAME to get pod name and then get pod index based on that and select a slack token key based on that index

[codecov]

Codecov Report

Attention: 17 lines in your changes are missing coverage. Please review.

Files	Coverage Δ
main.go	20.58% <55.26%> (+20.58%)	⬆️

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