Built first draft of workspace serialization schemas, started writing DB tests

Co-Authored-By: kay@zed.dev

crates/db/src/kvp.rs

@@ -3,7 +3,7 @@ use rusqlite::OptionalExtension;
 
 use super::Db;
 
-pub(crate) const KVP_M_1_UP: &str = "
+pub(crate) const KVP_M_1: &str = "
 CREATE TABLE kv_store(
     key TEXT PRIMARY KEY,
     value TEXT NOT NULL