Add firewall application along with other small improvements.

[labre-rdc]

Changes proposed in this pull request

• Add firewall application.
• Fix a few potential null dereferences in some validators and converters.
• Add ValidationErrorTemplate for checkboxes.
• Allow ValidationError to be clicked out of the way (restores on hovering/keyboard focus).
• Fix ChildWindowStyle restricting the window size to 500 height instead of setting a default height.
• Reuse existing validators in empty variants where applicable.
• Make ListHelper.Modify generic. Avoid duplicates.
• PowershellHelper: Support commands exceeding command line length limit.
• NetworkInterfaceView: Fix all XAML warnings.
• ProfileChildWindow: Always scale to 85% of main window width. Required for wider content.
• Localized enum conversion (to/from int/string)
• Fixed 2 warnings in ProfileView while being at it.

Related issue(s)

• Fixes [New App] Firewall module/application #3259

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To-Do

• Update documentation to reflect this changes
• Update changelog to reflect this changes
• Replace PR number placeholders in changelog.

Contributing

By submitting this pull request, I confirm the following:

• I have read and understood the contributing guidelines and the code of conduct.
• I have have added my name, username or email to the contributors list or don't want to.
• The code or resource is compatible with the GNU General Public License v3.0.

[BornToBeRoot]

@labre-rdc thanks, i will review it when i have some time 😄