Too many refactors in one:

- Allowed adding ephemeral(ish) views and functions
- Moved message_count to a concrete database field
- Moved most proxy logic to a stored procedure
- Moved database files around and refactored schema manager

PluralKit.Core/Migrations/1.sql

@@ -1,15 +0,0 @@
--- SCHEMA VERSION 1: 2019-12-26
--- First version introducing the migration system, therefore we add the info/version table
-
-create table info
-(
-    id int primary key not null default 1, -- enforced only equal to 1
-    
-    schema_version int,    
-    
-    constraint singleton check (id = 1) -- enforce singleton table/row
-);
-
--- We do an insert here since we *just* added the table
--- Future migrations should do an update at the end
-insert into info (schema_version) values (1);