cli - adds options to specifiy input and output file. adds help command

[xddq]

How to test

• help text should display: yarn build && yarn start -h
• should print generated output to stdout: yarn build && yarn start --output-stdout
• should use file with different name than default (types.ts) and default output (generated-types.ts). Make sure the files exist : p yarn build && yarn start -i types1.ts -o result.ts