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/Models/ModelQueryExt.cs

@@ -1,5 +1,4 @@
 #nullable enable
-using System;
 using System.Data;
 using System.Threading.Tasks;
 
@@ -9,19 +8,19 @@ namespace PluralKit.Core
 {
     public static class ModelQueryExt
     {
-        public static Task<PKMember?> QueryMember(this IDbConnection conn, int id) =>
+        public static Task<PKMember?> QueryMember(this IPKConnection conn, int id) =>
             conn.QueryFirstOrDefaultAsync<PKMember?>("select * from members where id = @id", new {id});
         
-        public static Task<GuildConfig> QueryOrInsertGuildConfig(this IDbConnection conn, ulong guild) =>
+        public static Task<GuildConfig> QueryOrInsertGuildConfig(this IPKConnection conn, ulong guild) =>
             conn.QueryFirstAsync<GuildConfig>("insert into servers (id) values (@Guild) on conflict do nothing returning *", new {Guild = guild});
 
-        public static Task<SystemGuildSettings> QueryOrInsertSystemGuildConfig(this IDbConnection conn, ulong guild, int system) =>
+        public static Task<SystemGuildSettings> QueryOrInsertSystemGuildConfig(this IPKConnection conn, ulong guild, int system) =>
             conn.QueryFirstAsync<SystemGuildSettings>(
                 "insert into member_guild (guild, member) values (@guild, @member) on conflict (guild, member) do update set guild = @guild, member = @member returning *", 
                 new {guild, system});
 
         public static Task<MemberGuildSettings> QueryOrInsertMemberGuildConfig(
-            this IDbConnection conn, ulong guild, int member) =>
+            this IPKConnection conn, ulong guild, int member) =>
             conn.QueryFirstAsync<MemberGuildSettings>(
                 "insert into member_guild (guild, member) values (@guild, @member) on conflict (guild, member) do update set guild = @guild, member = @member returning *",
                 new {guild, member});