Another resources cleaning

[Reco1I]

res/layout/:

• Removed activity_opening.xml since is a simple layout there's no necessary to keep a whole layout file for it, i replaced it with a LinearLayout object created programmatically.
• Removed dialog_clear_pp.xml, fragment_preview_background_brightness.xml, frg_test.xml, main.xml that are not used.

res/drawable/:

• Removed icon.png and its resource variants that are not used.
• Removed ic_new_icon.png and its resource variants that are not used.
• Removed notify_icon.png and its resource variants that are not used.

src/:

• Removed TestFragment.java because is not used (Is related to the removed file frg_test.xml).
• Replaced activity_opening.xml usage in PermissionActivity class with a LinearLayout object.

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