Improved exception management

[stanislav-bedunkevich]

Revise the exception hierarchy and ensure the information passed within the exception is elaborate enough for the user to act based on the exception type.

This includes handling of exception swallowing in the tests:
try { client.DeleteDatabaseAsync(Dbname).Wait(); } catch {}
where we'd like to log the exception if it actually occurs.

[billscheidel-rai]

Note: This issue has been migrated to https://relationalai.atlassian.net/browse/RAI-6209.

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