[GreyNoise] Add transform pipeline for package

[niraj-crest]

• 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