Add support for the componentmetadata endpoint

[meryllblanchet]

See https://adobedocs.github.io/analytics-2.0-apis/#/component-metadata%20-%20tags

cc @sarahxxu would you need to confirm some use-cases with the Adobe Analytics team?

[aiojbot]

JIRA issue created: https://jira.corp.adobe.com/browse/ACNA-1021