[SE-2761] Address docs issues: miscellaneous minor issues

This merge request is about addressing multiple miscellaneous minor issues related to the onboarding course.

• Newcomers should set their notifications to track changes to documentation group (issue)
• Add a description template to "Process: Pull Requests > Organization OpenCraft" (issue)
• Reorganise "Task Work Flows", move grooming points to its own section (issue)
• Confusing sentence in Task Workflows -> Internal review (issue)
• Bad link to "Testing Documentation" (issue)
• Should we be referring to "Open edX" rather than just "edX" everywhere in the handbook? (issue)
• Add terms to OpenCraft glossary (issue)
• Github email setup tips (issue)
• Add developer hardware specs to onboarding course (issue)
• Move epic ownership expectation to epic ownership description. (issue)
• Rename sprint "Grooming" to "Estimation" (issue)
• Newcomers should add their availability in the contact spreadsheet (issue)

Jira tickets

• SE-2761

Reviewers

• @jill_opencraft