Don't include bytecode in the main bundle by default

[davidyuk]

We find out that it can be quite big, up to 300kb. There 3 ways to handle bytecode:

• inline into generated contract.js (shouldn't be default)
• use async import in overriden $compile method (need investigate buildlers compatibility)
• don't include it at all

User should be able to choose one of these. I'm not sure about default.

was discussed in aeternity/aepp-boilerplate-vue#24