Layout improvements needed

[vtainio]

• [x] "Connected, aware and safe" icons needs to be smaller and the gap between the icons and the red text should be bigger.
• [x] "Our sponsors, our inspiration" section's text should be the same width as other texts on the same page.
• [x] The gap between two lines in the headers such as in "How does it work" should be smaller.
• [x] The link to Github in "Ready to contribute" should have a similar style as other buttons in the page.

[luisramalho]

Fixed with these:

• 3fe08d5 - Ready to contribute button now uses the same style as other buttons
• fc2d6f2 - Margin between header and subheader is now smaller
• 3374f4f - Sponsors text is the same width as other texts on the same page
• bcd460e - Icons are smaller and there's more margin between them