feat: Build /what-is-postgresql page

[petesfrench]

Done

• Build the 'what-is-postgresql' page based on the copydoc and design

Flyby

• Remove unused comment from styles.scss

QA

• Check out the demo
• Check that the content matches that in the copydoc
• Check the content is visible and logically laid out on all screen sizes

Issue / Card

Fixes https://warthogs.atlassian.net/browse/WD-13768

[webteam-app]

Demo

Jenkins

demos.haus

[petesfrench]

@mattea-turic This is ready for review, just waiting on some the assets

[lizzochek]

Was it agreed to remove this image or are we waiting for it?

[lizzochek]

Please get design approved and image added and ping me for another review in case of any changes

[mattea-turic]

This was mb as I did have it like that in the design, but could you remove the two 24px of padding so that only the 64px remains?

And could you pls use the same styling for this section:

As you did for this section:

Currently, the HOCs have some deprecated items so iirc I was swapping the layers in that first section to use from the updated library. But I suppose I forgot to do it for the second section which has caused inconsistency between them now. So, I think I'll avoid messing with the layers of the HOCs to avoid this in the future, esp. since there'll ofc be updates in the future

[petesfrench]

@mattea-turic Can you take another look here. I have upgraded the Vanilla version. I also applied some minor changes to https://canonical-com-1368.demos.haus/core/features/ota-updates

[mattea-turic]

as per my comment in MM, it looks good and I'll design +1 pending the change(s)