Several more database-y refactors

- DbConnectionFactory renamed to "Database", will now be the primary entry point for DB stuff
- Created IPKConnection interface mostly containing async extensions to IDbConnection, use this going forward
- Reworked the Connection/Command wrappers (that have performance/logging extensions)
- Probably more stuff that I forgot???

PluralKit.Core/Utils/ConnectionUtils.cs

@@ -7,21 +7,21 @@ using Dapper;
 namespace PluralKit.Core {
     public static class ConnectionUtils
     {
-        public static async IAsyncEnumerable<T> QueryStreamAsync<T>(this DbConnectionFactory connFactory, string sql, object param)
+        public static async IAsyncEnumerable<T> QueryStreamAsync<T>(this Database connFactory, string sql, object param)
         {
-            using var conn = await connFactory.Obtain();
+            await using var conn = await connFactory.Obtain();
             
             await using var reader = (DbDataReader) await conn.ExecuteReaderAsync(sql, param);
             var parser = reader.GetRowParser<T>();
-            while (reader.Read())
+            while (await reader.ReadAsync())
                 yield return parser(reader); 
         }
         
-        public static async IAsyncEnumerable<T> QueryStreamAsync<T>(this IDbConnection conn, string sql, object param)
+        public static async IAsyncEnumerable<T> QueryStreamAsync<T>(this IPKConnection conn, string sql, object param)
         {
             await using var reader = (DbDataReader) await conn.ExecuteReaderAsync(sql, param);
             var parser = reader.GetRowParser<T>();
-            while (reader.Read())
+            while (await reader.ReadAsync())
                 yield return parser(reader); 
         }
     }