Confusing error when request is targetted for an invalid tenant id

[lmsurpre]

Describe the bug
Requests for an invalid tenant are coming back with a response like this:

{"resourceType":"OperationOutcome","id":"c0-a8-1-da-7c8d79ec-4bc3-4d6b-940b-d755e1bb4f24","issue":[{"severity":"fatal","code":"exception","details":{"text":"FHIRPersistenceException: fhirServer/persistence/factoryClassname is configured incorrectly"}}]}

To Reproduce
Steps to reproduce the behavior:

1. deploy the server with the default connfig
2. make a request with a header like X-FHIR-TENANT-ID: dummy

Expected behavior
The request should come back with a clear error message that states that the tenant wasn't valid

Additional context
In #639 we decided that all tenants should have their own datasources (and should never "fall back" to the default one).
Based on this, we should be able to check for the presence of a tenant up front (based on the existence of the corresponding tenant config directory). Maybe we should put it right in the FHIRRestServletFilter?

[prb112]

Describe the bug
Requests for an invalid tenant are coming back with a response like this:

{"resourceType":"OperationOutcome","id":"c0-a8-1-da-7c8d79ec-4bc3-4d6b-940b-d755e1bb4f24","issue":[{"severity":"fatal","code":"exception","details":{"text":"FHIRPersistenceException: fhirServer/persistence/factoryClassname is configured incorrectly"}}]}

To Reproduce
Steps to reproduce the behavior:

1. deploy the server with the default connfig

2. make a request with a header like `X-FHIR-TENANT-ID: dummy`

Expected behavior
The request should come back with a clear error message that states that the tenant wasn't valid

Additional context
In #639 we decided that all tenants should have their own datasources (and should never "fall back" to the default one).
Based on this, we should be able to check for the presence of a tenant up front (based on the existence of the corresponding tenant config directory). Maybe we should put it right in the FHIRRestServletFilter?

I hit a similar issue with an old derby db in place

at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at java.base/java.lang.Thread.run(Thread.java:836)
Caused by: com.ibm.fhir.persistence.exception.FHIRPersistenceException: Unexpected exception while creating JDBC persistence layer:   [probeId=c0-a8-56-14-550264d1-9a69-4f98-a7db-c1956d072bfe]
	at com.ibm.fhir.persistence.jdbc.FHIRPersistenceJDBCFactory.getInstance(FHIRPersistenceJDBCFactory.java:32)
	at com.ibm.fhir.persistence.helper.FHIRPersistenceHelper.getFHIRPersistenceImplementation(FHIRPersistenceHelper.java:86)
	... 64 more
Caused by: java.lang.IllegalStateException: createCache failed
	at com.ibm.fhir.persistence.jdbc.cache.FHIRPersistenceJDBCTenantCache.getCacheForTenantAndDatasource(FHIRPersistenceJDBCTenantCache.java:41)
	at com.ibm.fhir.persistence.jdbc.FHIRPersistenceJDBCFactory.getInstance(FHIRPersistenceJDBCFactory.java:29)
	... 65 more