Dialogs need to handle soft keyboard without obscuring data or looking ugly

[Zhao Fan]

Bug detailed description:
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In current image, if invoke softkeyboard, some big dialogs, such as preference dialog will look ugly, so we need an implementation to make dialogs handle soft keyboard without obscuring data or looking ugly

Reproduce steps:
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(1) Launch midbrowser
(2) Choose menu Tools -> Preferences
(3) Invoke the soft keyboard

Current result:
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Some tabs with a lot of sectons will look ugly if soft keyboard is invoked

Expected result:
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The dialog should display properly even if soft keyboard is enabled

Basic root-causing log:
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[Zhao Fan (fan-zhao)]

Just noticed that the view certificate dialog will be obscured even if soft keyboard is not enabled. The close dialog button will even be hidden on the small screen, so I think the finger scroll is still needed for this dialog. so I change the milestone to m11. Carl, let me know if you have different opinions.

[Zhao Fan (fan-zhao)]

But downgrade the importance to medium since it's not so critical