* Fix for shared snapshot parameter
Fixing this bug:
`Unknown parameter in input: "IsShared", must be one of: DBInstanceIdentifier, DBSnapshotIdentifier, SnapshotType, Filters, MaxRecords, Marker, IncludeShared, IncludePublic, DbiResourceId`
* Updated documentation for shared snapshots
Tags can't get accessed for shared snapshots
* fixed indentation
* added test for shared snapshot
* fixed isPublic parameter to correct IncludePublic parameter
Co-authored-by: Oliver Kastler <oliver@realestate.co.nz>