docs: build custom integration guide added

[ashutosh-revert]

Description

Added guide to build & contribute custom third party integration

Fixes #353

Type of change

• [X] This change requires a documentation update

Checklist:

• [X] My code follows the style guidelines of this project
• [X] I have performed a self-review of my code
• [X] I have made corresponding changes to the documentation
• [X] My changes generate no new warnings

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Name	Status	Preview	Comments	Updated (UTC)
revert-client	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Feb 14, 2024 9:27am

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