Update Footer text, text styles, link styles, and responsive design

[ginny-d]

🔗 Figma link to component

• Terms should link to https://www.hiro.so/terms and Privacy should link to https://www.hiro.so/privacy
• Add Hiro Systems PBC mention
• On the left side should be explorer navigation links, in darker color
• On the right side should be secondary links, in lighter color