Switching from AVM interpreter to AVM workers

[coder11]

This PR is the tip of the iceberg of moving from hard-wired AVM interpreter to the general AVM worker abstraction. It allows to run the interpreter differently e.g in background thread using web worker or worker threads.

The changes in current repo include:

• getting rid of @fluencelabs/avm dependency
• injection AvmRunner instead of using hard-wired interpreter through the config
• providing the default implementation for backward compatibility.

Other changes include new packages:

https://github.com/fluencelabs/avm-runner-interface
https://github.com/fluencelabs/avm-runner-background

fluencelabs/avm update:

fluencelabs/aquavm#200

examples repo update:

fluencelabs/examples#39

dashboard update:

fluencelabs/dashboard#28

and documentation update:

fluencelabs/gitbook-docs#30