Layer5: [Brand] Add smooth navigation transition to sidebar menu

[leecalcote]

Current Behavior
On the https://layer5.io/brand page, when a user clicks on the links in the sidebar navigator (see screenshot), the transition to the respective section is not smooth.

Desired Behavior
Upon click, the page should smoothly scroll (transition) to the desired section and not do so abruptly.

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Contributor Resources

The layer5.io website uses Gatsby, React, and GitHub Pages. Site content is found under the master branch.

• See contributing instructions
• See Layer5 site designs in this Figma project.

[chinmaym07]

Can I knock this ?

[leecalcote]

Sounds great, @chinmaym07. Looking over these others, we might want to close out the first of these regarding the presentations on Meshery. I'm not sure that we want to carry that one through at the moment. We can always reopen.