Replace deprecated OpenSauced app login/signup references

[BekahHW]

Problem

The documentation contains multiple references to app.opensauced.pizza that instruct users to sign up for accounts and use interactive features. Since OpenSauced platform functionality is deprecated, these instructions no longer work.

Files to Update

• docs/intro-to-oss/how-to-contribute-to-open-source.md - Contains signup instructions
• docs/intro-to-oss/the-secret-sauce.md - References account creation
• docs/becoming-a-maintainer/metrics-and-analytics.md - Login instructions for workspace creation

Suggested Solution

Replace with alternatives such as:

• Contributor.info for portfolio building
• GitHub native tools for repository tracking
• Remove non-functional signup instructions

Acceptance Criteria

• All app.opensauced.pizza references removed or updated
• Alternative solutions provided where applicable
• Documentation flows still make sense without deprecated features

Priority: High
Good for: Intermediate contributors
Estimated effort: 2-3 hours

[Shreyas-Walde]

@BekahHW Hey, I'm already working on this was about to raise an PR then i so this. Please assign it to me.

[adiati98]

@Shreyas-Walde, you're assigned to the issue!

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