Milestone 2 (#6)

* add new contract

* update deps, update readme

* WIP call transfer from contract

* pass args to transfer func

* add test contract, readme

* add payable

* update readme

* remove test, transfer assets works, add registry, add mint func

* add purchase func

* update readme

* update email

* purchase tokens with latest chain ext funcs

* update ext

* update chain ext, add new errors, add event struct, lock and transfer works

* cleanup, add docs

* update readmes, add composable access rules

* limited use token

* remove cars

* happy path tests work

* update get version func

* update storage maps

* rename func

* add getters for registries

* fix typos, handle option

* update structure, CARs WIP

* compilation works

* register func works

* update gitignore

* add limit to constructor

* register works, tests work, execute works

* limited use token works with burn

* rule executor works

* modify storage with new struct, update tests, remove chain ext

* move data retrieval to compoasable rules dir, create trait for rule executor

* cross contract calls works!

* :(

* rule executor works

* rename data_retrieval to rule executor, update docs

* update docs, cleanup

* update readme and .gitignore

* add license

* add copyright headers

* update to pass pk as arg from caller

* add trivial executor

* remove target

Author: driemworks