Support terminals with ssh in remote projects (#11913)

Release Notes:

- Added a way to create terminal tabs in remote projects, if an ssh
connection string is specified

crates/collab/migrations.sqlite/20221109000000_test_schema.sql

@@ -407,6 +407,7 @@ CREATE TABLE dev_servers (
     id INTEGER PRIMARY KEY AUTOINCREMENT,
     user_id INTEGER NOT NULL REFERENCES users(id),
     name TEXT NOT NULL,
+    ssh_connection_string TEXT,
     hashed_token TEXT NOT NULL
 );