[git] Git: How to reset a remote Git repository to remove all commits?

Were I you I would do something like this:

Before doing anything please keep a copy (better safe than sorry)

git checkout master
git checkout -b temp 
git reset --hard <sha-1 of your first commit> 
git add .
git commit -m 'Squash all commits in single one'
git push origin temp

After doing that you can delete other branches.

Result: You are going to have a branch with only 2 commits.

Use git log --oneline to see your commits in a minimalistic way and to find SHA-1 for commits!