Add portfolio optimization environment (#309)

* Create portfolio allocation env

* Refactor state of portfolio allocation env

* Refactor class params

* Fix bugs in portfolio value

* Add enumerate portfolio function

* Fix portfolio value calculations

* Add transaction remainder factor

* Add portfolio normalization

* Add gym api version parameter

* Add other normalization methods

* Add wvm comission fee

* Add transaction remaining factor comission model

* Remove old documentation

* Add quantstats visualizations

* Change portfolio optimization env name

* Create portfolio optimization folder

* Fix observation space

* Change initial portfolio distribution

* Remove unnecessary methods

* Add dict observation space

* Add methods documentation

* Add class documentation

* Refactor class attributes

* Improbe normalization condition

* Add time index to info dict

* Update documentation

* Upload example using POE

* Upload POE example notebook

* Update POE example

* Add POE readme

* Fix typo

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>