Add Form based events and dimensions to ExperienceEvent

## What are the schemas that are affected by the issue
https://github.com/adobe/xdm/blob/master/schemas/data/metrics.schema.json
Some new way of representing standard Form dimensions.

## What are examples of products that are impacted by the issue
AEM Forms -> the team contributing the information for the proposal.

Currently in use today:

Success Event | Type
-- | --
abandon | Counter
render | Counter
panelVisit | Counter
fieldVisit | Counter
save | Counter
error | Counter
help | Counter
submit | Counter

Dimensions:
· formName: Identifier for an adaptive form.
· formInstance: Identifier of an adaptive form instance. Enable Path reports for this variable.
· fieldName: Identifier of an adaptive form field. Enable Path reports for this variable.
· panelName: Identifier of an adaptive form panel. Enable Path reports for this variable.
· formTitle: Title of the form.
· fieldTitle: Title of the form field.
· panelTitle: Title of the form panel.
· analyticsVersion: Version of form analytics.

These are very standard concepts across many form implementations.

Start with schemas/data/metrics.schema.json and review the existing ExperienceEvent metrics alongside the listed form events and dimensions. Determine how the proposal should represent these concepts, then confirm that the schema covers the stated AEM Forms use cases and the requested standard form fields.

Written by the indexing model from the issue text.