Add initial version of TypeDB extension

[whummer]

Motivation

Add initial version of TypeDB extension. Migrating from the temporary repo used to build out the MVP, in collaboration with the TypeDB team: https://github.com/whummer/localstack-utils/tree/master/localstack-typedb

After installing the extension, a TypeDB server instance will become available under typedb.localhost.localstack.cloud:4566, allowing you to create and manage TypeDB databases directly from your AWS applications running in LocalStack.

For example, you could create a microservice backed by a Lambda function that connects to a TypeDB database upon invocation. See here for a simple example application that makes use of this extension.

This is part of a collaboration / co-branding with TypeDB, a blog post should be following soon.. (/cc @flyingsilverfin )

Changes

• add base class ProxiedDockerContainerExtension which can be used to define an Extension backed by a Docker container. We may be able to pull out this class into common utils over time.
• add ProxyResource class which is used as a resource that hooks into the LocalStack (rolo) handler chain and forwards matching requests to the extension container
• add ProxyRequestMatcher class which allows the extension to define which incoming requests are in scope and should be forwarded to the TypeDB container
• add TcpForwarder class to enable a bidirectional TCP proxy tunnel that forwards traffic to and from the external container
• add TypeDbExtension class which defines the main entrypoint for the extension
• add a couple of simple integration tests to cover the functionality