Feature request: Enhancement to Show on Map tool

I can see that the **Show on Map** tools supports several formats, but it currently lacks support for Maidenhead Locators.

[Maidenhead Locator System](https://en.wikipedia.org/wiki/Maidenhead_Locator_System)

Because the Maidenhead Locator system describes an area, rather than a specific point, then when converting between formats then it would make sense to use the centre point as the main co-ordinate. This would be a useful feature for many users, in particular amateur radio operators.

It would also be useful to include this in the **Convert co-ordinate format** tool.