[#232] Extend Indigo tutorial with information about full smart contract development

Description

Problem: Indigo tutorial describes language features that allow you to write contract code, but apparently it does not mention tools that let you and other people use your contract. In other words, how to go from just having Indigo code into a full project consisting Indigo contract(s).

Solution: Add a tutorial on how to setup an Indigo project for full smart contract development.

Related issue(s)

Resolves #232 (closed)

Depends on #180 (closed)

Depends on #270 (closed)

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