Add FAQ section to Portable Mode Docs

[nguyen-dows]

Add a FAQ section to the Portable Mode docs and address #665

[learn-build-service-prod]

Learn Build status updates of commit 226208c:

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[learn-build-service-prod]

Learn Build status updates of commit 1d7312f:

✅ Validation status: passed

File	Status	Preview URL	Details
TerminalDocs/distributions.md	✅Succeeded	View

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• Post your question in the Learn support channel

[learn-build-service-prod]

Learn Build status updates of commit b0dfe83:

✅ Validation status: passed

File	Status	Preview URL	Details
TerminalDocs/distributions.md	✅Succeeded	View

For more details, please refer to the build report.

For any questions, please:

• Try searching the learn.microsoft.com contributor guides
• Post your question in the Learn support channel