Scaden

* Changed datatype for data simulation back to `float32`

* Fixed bugs in scaden model definition [[88](https://github.com/KevinMenden/scaden/issues/88)]
* removed installation instructions for bioconda as not functional at the moment [[86](https://github.com/KevinMenden/scaden/issues/86)]
* Fixed bug in `scaden example` [[85](https://github.com/KevinMenden/scaden/issues/85)]

* Reduced memory usage of `scaden simulate` significantly by performing simulation for one dataset at a time.
* Using `.h5ad` format to store simulated data
* Allow reading data in `.h5ad` format for improved performance (courtesy of eboileau)
* Improved logging and using rich progress bar for training
* Gene subsetting is now done only when merging datasets, which will allow to generate different combinations
of simulated datasets
* Added `scaden merge` command which allows merging of previously created datasets

* General improvement of logging using the 'rich' library for colorized output
* Added verification check for '--train_datasets' parameter to notify user of
unavailable datasets

* Made identification of datasets more robust to fix issue [66](https://github.com/KevinMenden/scaden/issues/66)

* Rebuild Scaden model and training to use TF2 Keras API instead of the old compatibility functions
* added `scaden example` command which allows to generate example data for test-running scaden and to inpstec the expected file format
* added more tests and checks input reading function in `scaden simulate`
* fixed bug in reading input data