Hibernate ORM 6.3 introduced support for tenant identifiers of any type, in particular (but not only) when using @TenantId.

We should:

• test that Hibernate Search works well for applications using non-string tenant IDs (i.e. it converts them to strings transparently, allows mass indexing, …)

• add support for non-string tenant IDs in Hibernate Search.
  For the conversion, maybe we could use an IdentifierBridge? A tenant identifier is an identifier, after all.