feat: allow non-interactive input

[novusnota]

Closes #19

That is, the following and similar approaches are now possible:

./bin/index.js << EOF
package-name
ContractName
EOF

There, the input stream is supplied to the create-tact at once, such that it no longer needs to interactively prompt the user for input — a simple alternative to arbitrary CLI arguments (#8, #10).

Without this PR, the command above throws the following error: Error [ERR_USE_AFTER_CLOSE]: readline was closed.