almost finish refactoring PersistentCredential trait

src-tauri/migrations/20240617142724_credential_split.sql

@@ -41,13 +41,13 @@ CREATE TABLE credentials (
     -- id is a UUID so we can generate it on the frontend
     id BLOB UNIQUE NOT NULL,
     name TEXT UNIQUE NOT NULL,
-    type TEXT NOT NULL,
+    credential_type TEXT NOT NULL,
     is_default BOOLEAN NOT NULL,
     created_at INTEGER NOT NULL
 );
 
 -- populate with basic data from existing AWS credential
-INSERT INTO credentials (id, name, type, is_default, created_at)
+INSERT INTO credentials (id, name, credential_type, is_default, created_at)
 SELECT id, 'default', 'aws', 1, created_at FROM aws_tmp;
 
 -- new AWS-specific table