release a stable version of npm package under filecoin-project

[longfeiWan9]

After we moved filecoin-solidity to filecoin-project, we have not released npm package for devs to use under any filecoin-project account instead of Zondax. So if devs want to install filecoin-solidity, the only option for them is still @zondax/filecoin-solidity which point to the old Zondax version.
Actions need to be taken:

• release a stable version of filecoin-solidity, and published to npm with filecoin-project account. For example, @filecoin-project/filecoin-solidity
• update README and Filecoin docs so devs can use the right version.