Landing page clean-up

[elliotBraem]

1. The below content should be centered:

2. bos-workspace should show pointer and navigate to https://github.com/nearbuilders/bos-workspace on click

3. Quickstart guide should navigate to https://github.com/NEARBuilders/quickstart.near

4. Workspace docs should navigate to (network correct ${alias_gateway_url}) : https://test.nearbuilders.org/builddao.testnet/widget/Index?page=resources&tab=gettingStarted

5. "Start project" can go to https://test.nearbuilders.org/builddao.testnet/widget/Index?page=projects

6. "Explore tools" can go to https://docs.near.org/build/near-components/dev-environment

7. In footer, these should point to :

Twitter: https://x.com/NearBuilders
Telegram: https://nearbuilders.com/tg-builders
Github: https://github.com/NEARBuilders

8. "Activity" goes to https://test.nearbuilders.org/builddao.testnet/widget/Index?page=activity
9. Remove full footer block here: