Make 40MHz default and add 5MHz to channel widths

[raphaelscholle]

Make 40MHz default and add 5MHz to channel widths

Removes the 'dev_allow_40mhz' setting in all places and shows 40MHz channel width by default to all users. Includes changes to 'EditChannelWidthElement.qml' in the sidebar to properly list and scroll through the values. In addition, adds '5Mhz' as an option for channel widths in the UI and parameters.

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PR created automatically by Jules for task 10671526169746106221 started by @raphaelscholle

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