add cli code samples to the o1js README

[barriebyron]

from @stevenpack let's elevate our o1js README to new heights with o1-labs/docs2#552 and:

• cli code samples
• real code samples of a simple contract

I like the code explainers and architecture overview in https://github.com/lambdaclass/mina_bridge#readme

[barriebyron]

Inspiration for awesome README, see https://www.appsmith.com/blog/write-a-great-readme

see README guidance https://github.com/o1-labs/docs2/wiki/README-files