Restructure `node-binary` repo to use branches for versions instead of folders

[onggunhao]

Currently, cloning the node-binary repo results in is 5.6GB total. This should not happen if we are using git-lfs

Possible issue

• Am I using git-lfs incorrectly?
• lfs is incorrectly tracking certain files
• .gitattributes is incorrectly set up

Reproduction

# Install git lfs
brew install git-lfs
git lfs install --system

# Clone repo
# Note: this should be git clone, not git lfs clone (deprecated)
git lfs clone https://github.com/binance-chain/node-binary.git 

# Get size estimates
du -sh ./node-binary

Initial download is >1GB

Total downloaded file size is >5GB

[onggunhao]

We can solve this by using branches to store node-binary versions, instead of folders.

Currently, a git lfs clone pulls down all node-binary versions, which will only bloat with time

Example: Bitcoin's version branches

This also helps with CI, which can just test the latest node-binary without having to know the version number.

cc @huangsuyu