Remove contract name for add and update contract command

[sukantoraymond]

Closes #231

This PR enables users to add and update contract without using contract name. It will extract contract name from contract source code.

---

For contributor use:

• [x] Targeted PR against master branch
• [x] Linked to Github issue with discussion and accepted design OR link to spec that describes this work
• [x] Code follows the standards mentioned here
• [x] Updated relevant documentation
• [x] Re-reviewed Files changed in the Github PR explorer
• [x] Added appropriate labels

[sukantoraymond]

I don't think its necessary to make contract name optional in the add / update contract command? We can just remove it altogether @sideninja

[devbugging]

@sukantoraymond we need to keep it due to backward compatibility.