Add Schema Collections to documentation.

Author: bgrainger

docs/content/overview/schema-collections.md

@@ -0,0 +1,45 @@
+---
+date: 2021-04-24
+menu:
+  main:
+    parent: getting started
+title: Schema Collections
+customtitle: "Supported Schema Collections"
+weight: 80
+---
+
+# Supported Schema Collections
+
+`DbConnection.GetSchema` retrieves schema information about the database that is currently connected. For background, see MSDN on [GetSchema and Schema Collections](https://docs.microsoft.com/en-us/dotnet/framework/data/adonet/getschema-and-schema-collections) and [Common Schema Collections](https://docs.microsoft.com/en-us/dotnet/framework/data/adonet/common-schema-collections).
+
+`MySqlConnection.GetSchema` supports the following schemas:
+
+* `MetaDataCollections`—information about available schemas
+* `CharacterSets`
+* `Collations`
+* `CollationCharacterSetApplicability`
+* `Columns`
+* `Databases`
+* `DataTypes`—information about available data types
+* `Engines`
+* `KeyColumnUsage`
+* `KeyWords`
+* `Parameters`
+* `Partitions`
+* `Plugins`
+* `Procedures`—information about stored procedures
+* `ProcessList`
+* `Profiling`
+* `ReferentialConstraints`
+* `ReservedWords`—information about reserved words in the server's SQL syntax
+* `ResourceGroups`
+* `SchemaPrivileges`
+* `Tables`
+* `TableConstraints`
+* `TablePrivileges`
+* `TableSpaces`
+* `Triggers`
+* `UserPrivileges`
+* `Views`
+
+The `GetSchema(string, string[])` overload that specifies restrictions is not supported.