Druid Metadata Storage extensions are not pluggable due to varying sql implementations

[mark1900]

Basically adding Druid Metadata Storage extensions for differing databases is tricky due to how JDBC sql calls are made.

Below is a quote in response to my effort on creating a Metadata Storage extension for Microsoft SqlServer (sqlserver-metadata-storage). See #3421

To quote @drcrallen

Can you file an issue about this?

The fact that these aren't pluggable for varying sql impls is not ideal. This shouldn't have to have a this kind of translation.

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