[Feature]: "Delete" feeds

[gvensan]

Feature Description

What constitutes a delete feed a) in local stm feeds setup and b) in community feeds. Explore and organize a clean way of deleting feeds.

Use Case

Say, an feed got updated with schema or other attributes that will require creation of a new feed - need a clean way to remove the existing feed.

Proposed Solution

a) Local feed - a delete is straight forward, removal of feed folder from the $STM_HOME/feeds would suffice
b) Community feed - requires deletion of feed folder and removal of feed definition from the EVENT_FEEDS.json, both would require a PR.