Add Google ADK integration (#30)

* google adk init example

* google adk init example

* update middleware

* wip: add agent and quiz agent

* Init

* trial

* trial

* trial

* trial

* trial

* trial

* working initial version of ADK + A2A + Restate

* fix bug in restate session service

* create restaterunner to hide setup

* restructure and try more examples

* tour examples

* uuid patch

* human approval agents

* multi agents examples

* Format

* subworkflows and parallel agents

* Format

* Remove comment

* Fix a2a samples to use ADK

* Make examples more concise

* Improve code conciseness

* Fix cancellation and get task

* Small fixes to a2a examples

* ADK example

* A2A readme

* Fix broken links

* Add WIP note

* Fix broken links

* Implement as plugin

* Implement as plugin

* pull id patching out of adk plugin

* pull id patching out of adk plugin

* raise terminal tool and llm call errors

* use restate_overrides in handlers

* upgrade adk and fix restate service context

* improve readme

* improve commenting of basic example

* improve readme

* fix small issues

* if suspension issues

* update middleware and examples

* Generate function IDs within ctx.run

* Cleanup

* cleanup final response parsing

* Fix a2a examples

Author: gvdongen