Add lightbend banner

[rasummer]

@marcospereira here's the PR for the Lightbend Banner for Lagom.

Due to the fact that this site has a fixed nav on scroll, I decided to refactor the main nav code and rebuild a bunch of css as it was easier than trying to make it work as is. End result is cleaner and it works nicely on all screen sizes.

Updated the main home page hero text per Oliver's request. Also added Google Tag Manager for the purpose of triggering analytics.

[ignasi35]

Hi @rasummer this looks great and the way both headers scroll up and only the classic one anchors is very smooth. I noticed a small change in style and wanted to double-check it is intentional:

This is how the classic, live header looks when scrolling (notice the font is bold and the alignment):

Running this PR on my machine It seems to me the font is not longer bold and the categories align center. Is this correct?

(bonus) The Lagom logo on the anchored header is now slightly bigger but also better aligned (IMHO) on the header, but that didn't call my attention until I frantically switched tabs so I guess it wasn't as obvious (or important).

[rasummer]

Yes it was intentional.

The fixed/sticky purple menu got rebuilt with simpler HTML markup and CSS Flexbox as it was proving tough to incorporate with the addition of the LB banner across all screen sizes.

The centering of the navigation links are a result of moving the Flexbox. I could start to complicate the markup and css again to get it back to a point that it's exactly like the old nav, but I felt like this newer layout looked and worked just fine.

I did change the font from bold to normal, mainly cause I'm a designer and I like changing stuff. I'm happy for it to be either. Let me know if you'd like it to be bold.

Best Rich