feat: add chevron open/close component

[alexbarnsley]

Summary

Related to https://app.clickup.com/t/1npyzb6

Required by ArkEcosystem/explorer#1018

This is the icon that's used in a few places (e.g. navbar dropdown)

Note: the transform css class makes the chevron rotate counter-clockwise. By default it's clockwise. I kept these in place when updating to use the component. This could possibly be a property instead though if it is actually intended to reverse (reverse-rotation) @ItsANameToo? 🤔

Also contains a couple of tweaks to the mobile navbar children dropdown - it was hardcoded to output "Products" instead of whatever the menu item was called. I kept the change here as I noticed it when updating to use the chevron component

Checklist

• I checked my UI changes against the design and there are no notable differences
• I checked my UI changes for any responsiveness issues
• I checked my (code) changes for obvious issues, debug statements and commented code
• I provided a screenshot of my changes to the component (if applicable)
• I regenerated the icons.html file and checked if my newly added icon is shown correctly (if necessary)
• I added an explanation on how to use the component to the readme (if necessary)
• Documentation (if necessary)
• Tests (if necessary)
• Ready to be merged

[leMaur]

@alexbarnsley Few adjustments, other than that I think it's good to have this sort of components 👍🏼

[leMaur]

@alexbarnsley 👍🏼 all good to me