Add examples/ in the repo

[lazysegtree]

We could add around 5-10 common usage examples in examples/ directory with this format

file - descriptive_name.go

content -

<go code>
/* 
<Detailed explanation of what program does if needed>

<Equivalent shell script>
*/

• Makes it easy for new users to understand the API
• Makes it easy for users to implement a solution for them, by providing them a reference of real world use cases
• It allows providing larger examples that cannot fit in ReadMe
• It allows providing more examples, as Readme cannot fit too many examples.
• Its standard practive

Bonus

• We could add some sort of check in GitHub Actions to ensure all examples runs. That will be a good intergeration test.

[lazysegtree]

I just noticed that go docs (https://pkg.go.dev/github.com/bitfield/script) already has many low-scope, per-function examples. So the above suggestion might not really be that useful.

Still we could benefit from larger examples that demonstrate more realistic use cases

@bitfield let me know what you think about this.