Create Why Feast page

[franciscojavierarceo]

Is your feature request related to a problem? Please describe.
We need a document in github explicitly answering the question "Why Feast?". There are a lot of feature stores, a one pager should outline why Feast in particular is useful.

Describe the solution you'd like
A doc in GitHub that is also linked in the "Why Feast" footer on the homepage.

Here are some ideas:

1. All of the reasons you should use a Feature Store +
2. Complete Observability into an important system
3. Don't have to send date outside of your environment
4. Part of the Kubeflow Ecosystem
5. Community Support
6. Vendor Lock-in Avoidance
7. Customization
8. Cost Efficiency
9. Security/Governance

Some useful resources:

• https://www.tecton.ai/blog/devops-ml-data/
• https://medium.com/@ongxuanhong/mlops-03-feast-feature-store-an-in-depth-overview-experimentation-and-application-in-tabular-b9d1c5376483
• https://www.datarevenue.com/en-blog/feature-store-feast-vs-hopsworks

Describe alternatives you've considered
N/AS

Additional context
See footer that is a broken link which I will update to point to the docs for now.

[franciscojavierarceo]

Would love thoughts from @tokoko @HaoXuAI @shuchu on this one.