adds field for specifying assets URLs for thumbnails

[Mike Reynolds (MikeDReynolds68)]

Purpose

This branch includes the following changes:

• adds the installation parameter assetsUrlRoot which allows customers to set the root to be used when generating asset thumbnail URLs
• updates the transformAssets function to accept a config parameter and use its assetsUrlRoot property to modify each asset's thumbUrl if not null
• removes repositoryId, aemTierType, and env from the contentAdvisorProps object instantiation and makes them conditional
• updates the descriptions for repositoryId, aemTierType, and env in the setup function to clarify their conditional usage
• updates the descriptions for repositoryId, aemTierType, and env and adds assetsUrlRoot in the Installation Parameters table of the README.md file

Approach

The addition of the assetsRootUrl field was necessary to allow Ralph Lauren to generate a valid thumbnail URL for assets selected from their author environment which does not provide publicly accessible asset URLs.
The change to repositoryId, aemTierType and env was made to prevent the app from passing conflicting configuration parameters to the AEM Content Advisor micro front-end.

Testing steps

Test 1: Enter a valid AEM Assets base URL in the assetsUrlRoot and save the configuration. Open a content entry that uses the AEM Assets connector and click the button labeled 'Select assets from AEM'. Click on an asset in the Content Advisor modal window and then click the button labeled 'Select' in the top right corner. Inspect the thumbnail image generated by the AEM Assets connector and verify the asset URL base matches the value of the assetsUrlRoot configuration parameter.

Breaking Changes

None

Dependencies and/or References

None

Deployment

None