Dropdown for timezone in maintenance uses the default timezone

[ScottWilliamAnderson]

Making the dropdown for timezone in maintenance have the default value of the timezone from settings, instead of being empty

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Description

I'd like to set the default value of the dropdown in the maintenance scheduler to be set to the current value in the server's timezone. This is a very minor QOL improvement for users who often schedule maintenance & would use the same timezone as the server.

I've followed the guidelines from the CONTRIBUTING.md, and would like to have @louislam input if you think this is an appropriate new feature, I will start work on it. Please do share any comments or thoughts you might have.

Type of change

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• New feature (non-breaking change which adds functionality)

Checklist

• [ ] My code follows the style guidelines of this project
• [ ] I ran ESLint and other linters for modified files
• [ ] I have performed a self-review of my own code and tested it
• [ ] I have commented my code, particularly in hard-to-understand areas (including JSDoc for methods)
• [ ] My changes generates no new warnings
• [ ] My code needed automated testing. I have added them (this is optional task)

Screenshots (if any)

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[Ionys320]

The fix is easy to made, I guess you can submit it and wait for it to be approved. More of that, this should be the default comportment, referring to the Wiki!