This also temporarily disables couchbase, elasticsearch, and
mongodbatlas because the `Serve` function needs to change signatures
and those plugins are vendored in from external repos, causing problems
when building.
* Added HANA dynamic secret backend
* Added acceptance tests for HANA secret backend
* Add HANA backend as a logical backend to server
* Added documentation to HANA secret backend
* Added vendored libraries
* Go fmt
* Migrate hana credential creation to plugin
* Removed deprecated hana logical backend
* Migrated documentation for HANA database plugin
* Updated HANA DB plugin to use role name in credential generation
* Update HANA plugin tests
* If env vars are not configured, tests will skip rather than succeed
* Fixed some improperly named string variables
* Removed unused import
* Import SAP hdb driver
Michael Golowka