Auto-save file and trajectories when connected to a robot project

[shueja]

1. The file extension for a save file shall be .chor. For trajectories to be loaded in robot code, it shall be .traj.
2. The save file shall not include the trajectory samples.
3. Choreo should have an option to select a robot project build.gradle. When one is selected, the .chor file will save alongside it with a user-prompted name. The <pathname>.traj files will save in src/main/deploy/choreo with corresponding generated trajectories. If a trajectory has not been generated for the given path, the .traj file will not save at the time of selecting a build.gradle.