[Feature] Adds Image Generation Capability 2.0 (#1907)

* adds image generation capability

* add todo

* readded cache

* wip

* fix content str bugs

* removed todo: delete imshow

* wip

* fix circular imports

* add notebook

* improve prompt

* improved text analyzer + notebook

* notebook update

* improve notebook

* smaller notebook size

* made changes to the wrong branch :(

* resolve comments + 1

* adds doc strings

* adds cache doc string

* adds doc string to add_to_agent

* adds doc string to ImageGeneration

* instructions are not configurable

* removed unnecessary imports

* changed doc string location

* more doc strings

* improves testability

* adds tests

* adds cache test

* added test to github workflow

* compatible llm config format

* configurable reply function position

* skip_openai + better comments

* fix test

* fix test?

* please fix test?

* last fix test?

* remove type hint

* skip cache test

* adds mock api key

* dalle-2 test

* fix dalle config

* use apu key function

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Co-authored-by: Chi Wang <wang.chi@microsoft.com>