[CHEC-1932] Add new borders, background, and shadow props

[jaepass]

• Add new borders style, remove unused vertical and horizontal styles
• Add background as prop
• Add shadow as prop

Follow up PR with marketing card Contentful model edits
Reimplement dashboard and marketing site with new props

[linear]

CHEC-1931 Flesh out docs landing page from marketing page content model

We have decided to recreate the docs landing page (currently under /docs) as a marketing page where it will be the point of entry page to navigate to the SDK, API, technical blogs, starter projects etc.

This task is to go into Contentful and try to design out the new docs landing page with as many of the existing block content models we have and to make a note of what edits we need to make to these models or whether we need to add new ones.

A/Cs

• Create a new mock Content page in Contentful that includes all the models we need
• Make note of what edits we need to make for existing content models etc. the card blocks need to have new configuration for adding shadows

[linear]

CHEC-1932 Overhaul marketing cards and add docs card designs

Based on CHEC-1931, we need to overhaul all the marketing cards in Contentful's content model and implement them in code. Some of the current docs card designs do not exist in marketing pages right now ex. the short height and long width ones, cards with hovers, feature image etc. This task is to add new card designs by adding new configuration fields in the content model 'Marketing | Block | Card'.

A/Cs:

• Add new field configuration in Marketing | Block | Card
• Make the necessary edits in the marketing project code

[robbieaverill]

Do you want to set a lighter text colour when using the dark background, or leave that up to the implementor?

[robbieaverill]

LGTM, nice work

[jaepass]

I think we can leave this up to the implementor as we have transparent as a background option too