Enhanced configuration for indexing Product information

By adding Client Logging information to the Search Indexing Configuration you can now find out who changed this project configuration and when it was changed.

• [API] Added lastModifiedBy and lastModifiedAt fields to SearchIndexingConfigurationValues
• [GraphQL API] Changed the SearchIndexingConfigurationValues type:
  • Added the lastModifiedBy field to the SearchIndexingConfigurationValues type.
  • Added the lastModifiedAt field to the SearchIndexingConfigurationValues type.

The following changes were introduced in terms of GraphQL SDL:

extend type SearchIndexingConfigurationValues {
  lastModifiedAt: DateTime
  lastModifiedBy: Initiator
}