reorganize and rename of each section...

[Chalmer Lowe]

Suggest the following changes and renaming to the broad layout/structure:

• lesson one: introduction (ie. welcome students, help them understand the workshop and what we will accomplish) - lesson_01_workshop_intro.md
• lesson two: tools for sprinting (introduce the tools to be used and install them) - lesson_02_tool_installation.md
• lesson three: virtual environments overview - lesson_03_venv_overview.md
• lesson four: github overview - lesson_04_github_overview.md
• lesson five: git overview - lesson_05_git_overview.md
• lesson six: project overview - lesson_06_intro_to_the_project.md
• lesson seven: contributing hands-on - lesson_07_hands_on.md

[Chalmer Lowe]

While revisiting this, some other naming tweaks became apparent to make the names consistent:
ie:
workshop_intro >>> intro_to_the_workshop

etc.

[Chalmer Lowe]

Committed changes for all the file names and added placeholders where necessary, with the right names.