fix: update broken links and open external links in new tab

[danieljcafonso]

What does it do?

• fixes issue with dockerfile missing permissions to set the working directory and user
• makes external links open on a new tab
• fixes broken links
• adds proper linking on some scenarios
• deletes broken links where we couldn't find a replacement
• always links in the repo instead of linking to the response url in some cases
• adds the advocates email on the training part in case people want to reach out with questions

[netlify]

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