Mainstream un-install process for extensions

[kavilla]

Similar to:
#14

The process is quite manual, in the same manner. If any extension depended on the extension that is being removed then we should clean up the other extensions. It also should clean up any configurations because this will cause issues if the shared opensearch_dashboards.yml as configurations from a config path it doesn't recognized anymore

Requirements:

• Extensions can remove with configurations
  • Research: Can this occur with an API?
  • Research: If only CLI then how to replicate actions if multinode
• Downtime is reduced to only when required for the browser.
  • Research: Should we briefly start another task that installs it the background and then restart the same thread or do we start a task that installs the extension and then scales up a new OpenSearch Dashboards process and migrate over.
• Call any OpenSearch APIs to un-install corresponding extension
• Minimum amount of impact to OpenSearch Dashboards
  • Research: is this supported out of the box via OpenSearch extensions