Added Post Incident Practices module

[tom-halpin]

Proposed changes

Added Post Incident Practices module

Types of changes

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• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, renaming)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Workflow change
• Documentation update (if none of the other choices apply)

Checklist

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• I have read the CONTRIBUTING doc.
• Lint passes locally with my changes.
• I have added necessary documentation (if appropriate).
• Any dependent changes have been merged and published in downstream modules

Further comments

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[tom-halpin]

@cpswan @ojacques @pberthonneau open sourcing Post Incident Practices module by way of a small thank you to the community given the very positive reaction to the Dojo since we launched it.

[adamdmharvey]

Looks great! Two minor points from my side but I can see this being super valuable in the community!