Add time convertion to DL (quarkfin#229)

Updated the signatures of Exchagne Rate Provider and Tickers Universe…

… Provider (quarkfin#219)

Adding unit tests for Bloomberg HistoricalDataProvider (quarkfin#210)

Fixed typing.Sequence imports (quarkfin#206)

Fix/improve documentation for users (quarkfin#188)

Heatmap updated (quarkfin#173)

API documentation (quarkfin#154)

* Removed dic container from api documentation
* Updated Installation prerequisites

Waterfall Chart Setup (quarkfin#125)

* waterfall chart setup
* added total bar to chart

DFTable - style header per level and style index per level in multiin…

…dex (quarkfin#121)

* Added header styling

Added index in DFTable (quarkfin#118)

* Added index in DFTable