Add support for --randomize and --ui options

[joonaskuisma]

This PR introduces two new command-line options to the Dependency Solver:

• --randomize: Enables randomized test order.

  • A custom random seed can be provided using the syntax VALUE;SEED, where the seed must be an integer. Since the general delimiter for prerunmodifier arguments is :, unlike in the Robot Framework syntax, a semicolon ; must be used as the delimiter instead.
  • Closes Feature Request: Add --randomize Option to DependencySolver #5

• --ui: Launches a simple UI that allows users to:

  • Select tests via a tree view
  • Visualize test dependencies using arrows
  • Closes Feature Request: Add Graphical User Interface (GUI) for DependencySolver #6

Note: The UI is currently in Beta. Feedback and bug reports are welcome. Its documentation will also be improved in future updates.