docs: update links; add withdraw rewards

[MSalopek]

Description

This PR updates homepage links and adds a section on withdrawind validator rewards.

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[mpoke]

LGTM

[mpoke]

nit: I see this as 01. (i.e., the enum list doesn't work)

[MSalopek]

Fixed

[shaspitz]

If were fixing links, this also needs to be changed to ./docs/old/testing.md

[shaspitz]

LGTM