doc: Improve the overall deployment documentation

[Tomiwa1]

What does this PR do?

Updates documentation

Related ticket

Fixes #862

Type of change

• Chore
• Bug fix
• New feature
• Documentation update

Check list

• Unit tests for any smart contract change
• Contracts and functions are documented

[alainncls]

Thanks a lot for this contribution @Tomiwa1 🙏
I've asked @arthur-remy to review the changes from a product perspective.
Also, I know the integration tests are failing, but don't worry, that's on me 😉

[Tomiwa1]

It's my pleasure. You can assign me to the remaining documentation issues, I'll take a look at them.

[arthur-remy]

Thanks a lot for your contribution @Tomiwa1 and sorry for the delay to review.
It's a great improvement to add tables to store deployment addresses. Adding the introduction and some of the other text changes don't feel as impactful as it adds some verbose from my perspective.

I suggest to do the following:

• Keep the great address table but split them into two tables, one for mainnets, the other for testnets, make the testnet one collapsible to save space
• A nice addition would be to add a short description of the role of each contract before the table as well
• Put "legacy" subgraph v1 url in a collapsible section to save space as well
• Deployment are useful but can probably be put in a dedicated .md file and just linked in the main REAME to save space