Support of delete tenant API

Overview:
When disable/purge mod-oai-pmh for a tenant, noticed database schema and roles were not removed. Please consider adding support of delete tenant API to be consistent with other modules.

Steps to Reproduce:

1. Disable mod-oai-pmh for a tenant with purge parameter true
2. Check database and noticed schema and roles remain

Expected Results:
Database schema and roles are gone

Actual Results:
Database schema and roles remain

Additional Information:
Please refer RMB documentation and maybe use other module as an example
https://github.com/folio-org/raml-module-builder#the-delete-tenant-api
[https://github.com/folio-org/mod-orders-storage/blob/v11.0.3/descriptors/ModuleDescriptor-template.json#L457
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Note: need to review API tests and make sure they are up-to-date.