Pin default package versions

What does this MR do?

Pins the versions of packages installed via gem, pip or npm.

Adds support for npm packages, and moves bundler and yarn to be installed by their respective package managers.

Why was this MR needed?

We need to pin versions

What's the best way to test this MR?

scripts/dev-vm --base-image mr-79-toolchain-10.15.img new      

# ssh with address & port, base VM password in 1password
ssh -o Port=8822 gitlab@10.221.188.124

# in the VM run tools
yarn

What are the relevant issue numbers?

Closes #68 (closed)