Add tags to examples and hide those marked as experimental

[reczkok]

closes #313

[iwoplaza]

Apart from the single nitpick, awesome work! 💚 🐸

[iwoplaza]

I wanted to bring back categories someday, especially when the amount of examples is going to increase, so maybe we could filter the examples as they are being rendered?

        {exampleCategories.map((category) =>
          (examplesByCategory[category.key] ?? []).map((example) => {
            if (example.metadata.tags?.some((tag) => excludeTags.includes(tag))) {
              return null;
            }
            
            return (
              <ExampleLink key={example.key} exampleKey={example.key}>
                {example.metadata.title}
              </ExampleLink>
            );
          }),
        )}

[iwoplaza]

( ◦°^°◦) 🌺