[GreyNoise] Add transform pipeline for package

[niraj-crest]

Waiting for elastic-package validation to be added, to open this PR.

• Enhancement

What does this PR do?

• Added transform pipeline to parse alerts.
• Mapped fields according to the ECS schema and added Fields metadata in the appropriate yaml files.
• Added dashboards and visualizations.

Checklist

• I have reviewed tips for building integrations and this pull request is aligned with them.
• I have verified that all data streams collect metrics or logs.
• I have added an entry to my package's changelog.yml file.
• I have verified that Kibana version constraints are current according to guidelines.

How to test this PR locally

• Clone integrations repo.
• Install elastic-package locally.
• Start elastic stack using elastic-package.
• Move to integrations/packages/ti_greynoise) directory.
• Run the following command to run tests. elastic-package test

[botelastic]

Hi! We just realized that we haven't looked into this PR in a while. We're sorry! We're labeling this issue as Stale to make it hit our filters and make sure we get back to it as soon as possible. In the meantime, it'd be extremely helpful if you could take a look at it as well and confirm its relevance. A simple comment with a nice emoji will be enough :+1. Thank you for your contribution!