Allow the user to choose the groups endpoint when generating a PWBI token

Problem/Motivation

Currently, the module uses the https://api.powerbi.com/v1.0/myorg/GenerateToken endpoint and a related payload (embed token body) to generate the embed token. However, users should also be able to use the https://api.powerbi.com/v1.0/myorg/groups/{GROUP_ID}/reports/{REPORT_ID}/GenerateToken to generate
a token in group (see Embed Token - Reports GenerateTokenInGroup)

Proposed resolution

• Add a new element on field that allows user to choose the Generate Token on Groups option
• Create an update function for already existing installations to create data for said element
• Add a hook to allow users to modify the payload that will be sent to the endpoint
• Add new function on client to retrieve the token on groups
• Create tests for functionalities

User interface changes

The users will be able to choose between the current token generation and generating a token in groups when created a PWBI embed field on an entity.

API changes

A hook will be available for users to modify the payload to send when generating a token in groups.

Data model changes

A new column will be added on the PowerBi Embedd Field to store which endpoint to use.