* Removes _builtin_ versions from mount storage where it already exists
* Stops new builtin versions being put into storage on mount creation/tuning
* Stops the plugin catalog from returning a builtin plugin that has been overridden, so it more accurately reflects the plugins that are available to actually run
Add plugin version to GRPC interface
Added a version interface in the sdk/logical so that it can be shared between all plugin types, and then wired it up to RunningVersion in the mounts, auth list, and database systems.
I've tested that this works with auth, database, and secrets plugin types, with the following logic to populate RunningVersion:
If a plugin has a PluginVersion() method implemented, then that is used
If not, and the plugin is built into the Vault binary, then the go.mod version is used
Otherwise, the it will be the empty string.
My apologies for the length of this PR.
* Placeholder backend should be external
We use a placeholder backend (previously a framework.Backend) before a
GRPC plugin is lazy-loaded. This makes us later think the plugin is a
builtin plugin.
So we added a `placeholderBackend` type that overrides the
`IsExternal()` method so that later we know that the plugin is external,
and don't give it a default builtin version.
* Support version selection for database plugins
* Don't consider unversioned plugins for version selection algorithm
* Added version to 'plugin not found' error
* Add PluginFactoryVersion function to avoid changing sdk/ API
This is part 1 of 4 for renaming the `newdbplugin` package. This copies the existing package to the new location but keeps the current one in place so we can migrate the existing references over more easily.
