feat: add overlap checkbox

[fdrgsp]

@tlambert03 what do you think about adding the allow_overlap option as a checkbox? I think it can be a useful one to have...

in this PR:

• add allow_overlap checkbox
• add order combobox

[tlambert03]

definitely.
while you're in here, can you add stuff for the new useq pr?

[tlambert03]

sorry, hit send too soon. I mean:

fix the max-width widgets (and use adaptive step while we're at it)

        # well area doublespinbox along x
        self.max_width = QDoubleSpinBox()
        self.max_width.setAlignment(Qt.AlignmentFlag.AlignCenter)
        self.max_width.setRange(1, 1000000)
        self.max_width.setValue(1000)
        self.max_width.setStepType(QDoubleSpinBox.StepType.AdaptiveDecimalStepType)
        # well area doublespinbox along y
        self.max_height = QDoubleSpinBox()
        self.max_height.setAlignment(Qt.AlignmentFlag.AlignCenter)
        self.max_height.setRange(1, 1000000)
        self.max_height.setValue(1000)
        self.max_height.setStepType(QDoubleSpinBox.StepType.AdaptiveDecimalStepType)

add order as well

        self.order = QComboBox()
        self.order.addItems([mode.value for mode in TraversalOrder])
        self.order.setCurrentText(TraversalOrder.TWO_OPT.value)

then add that to the layout and connect signals

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Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 90.07%. Comparing base (4c51583) to head (a4d7fa7). Report is 31 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #317 +/- ## ========================================== + Coverage 90.06% 90.07% +0.01% ========================================== Files 71 71 Lines 7919 7930 +11 ========================================== + Hits 7132 7143 +11 Misses 787 787 ```

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