Hide menu options that are not available

[jwrober]

Is your feature request related to a problem? Please describe. Right now, if a menu option is not applicable it is greyed out on the menu.

Describe the solution you'd like Instead let's not even show it on the menu to reduce confusion. This might also enable us to merge menus to reduce the number of them on our path to getting rid of them completely.

Describe alternatives you've considered None

Additional context None

[jwrober]

I would also include any buttons on the views, such as the toggle AI on the Nations view

[lmoureaux]

I would only drop those items that are not enabled in the rules (for instance, the spaceship when it's disabled). Someone could wonder why the button is not there and think that it's a bug: if it's grayed out it's clear that it's not available for some reason.