Clean up all git content

[sheenarbw]

• [x] There are two git intro topics. There should be one #118 https://umuzi-org.github.io/tech-department/topics/git/ https://umuzi-org.github.io/tech-department/topics/git/git-basics/

• [x] Add link to git cheatsheet to git basics topic #179

• [x] There are three seperate presentations here: #119 https://umuzi-org.github.io/tech-department/workshops/git-basics/ There should be one or zero

• [x] Git for teamwork workshop is empty. Add correct stuff - Already done but not deployed. RO Deployed on 31/10/2019 https://umuzi-org.github.io/tech-department/workshops/git-for-teamwork/

• [ ] Git and scrum resources tells recruits to follow bad practices. Clean up #120 https://umuzi-org.github.io/tech-department/topics/git/version-control-and-scrum/

• [x] Not DRY. Refer to correct git topic instead of linking straight to atlassian docs #121 https://umuzi-org.github.io/tech-department/topics/clean-code/data-science

[sheenarbw]

@ry-oc This should have checkboxes so we can see how far we are without having to click on all the things