Make size of the left side panel adjustable

Currently, the left side panel with the table name dropdowns is fixed size. It would be a better experience if you could adjust the size (similar to how you interact with files/folders in text editors). You should be able to click anywhere on the right border of the panel and drag it to the left or right to adjust size.

No files or tests are named. Start by locating the frontend component that renders the left panel with the table name dropdowns and read how its current width is set. Done means the panel's right border can be dragged left or right to adjust its width, matching the behavior described in the issue.

Written by the indexing model from the issue text.