Add terraform init helper argument

Currently, I'm using the following commands to upgrade all providers/modules and ensure that we have lockfile hashes for all architectures.

logan --writable-workdir terraform init -upgrade

logan --writable-workdir terraform providers lock \
    -platform=windows_amd64 \
    -platform=darwin_amd64 \
    -platform=linux_amd64 \
    -platform=darwin_arm64

This is a PITA to remember! I'd like to add an argument (maybe -i, --terraform-init) to run these two commands for us. This will also ensure that we are all doing this in the same way for each of our projects.