more consistent handling of restricted species

[ChrisBNEU]

Related to website issue 220. The specific issue with the website is fixed here. There are two bigger issues that were not addressed:

1. we are generating an unpaired electron on the X atom for resonance structures:

2. We do not have consistent restrictions for certain surface species. Should there be a blanket ban on having radicals near the surface? how about charged species? The current system of applying restrictions when they cause problems is cumbersome, if we can make more general rules that will save us time in the future.

[github-actions[bot]]

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