Add MDAS dataset

[nilsleh]

This PR adds the MDAS dataset, a small, but multimodal dataset over the city of Augsburg, Germany.

Dataset features:

* 3K DSM data
* 3K high resolution RGB image
* Original very high resolution HySpex airborne imagery
* EeteS simulated imagery with 10m GSD and EnMAP spectral bands
* EeteS simulated imagery with 30m GSD and EnMAP spectral bands
* EeteS simulated imagery with 10m GSD and Sentinel-2 spectral bands
* Sentinel-2 L2A product
* Sentinel-1 GRD product
* Open Street Map (OSM) labels

Dataset format:

* 3K_RGB.tif (Shape: (4, 15000, 18000)px, Data Type: uint8)
* 3K_dsm.tif (Shape: (1, 10000, 12000)px, Data Type: float32)
* HySpex.tif (Shape: (368, 1364, 1636)px, Data Type: int16)
* EeteS_EnMAP_2dot2m.tif (Shape: (242, 1364, 1636)px, Data Type: float32)
* EeteS_EnMAP_10m.tif (Shape: (242, 300, 360)px, Data Type: uint16)
* EeteS_EnMAP_30m.tif (Shape: (242, 100, 120)px, Data Type: uint16)
* EeteS_Sentinel_2_10m.tif (Shape: (4, 300, 360)px, Data Type: uint16)
* Sentinel_2.tif (Shape: (12, 300, 360)px, Data Type: uint16)
* Sentinel_1.tif (Shape: (2, 300, 360)px, Data Type: float32)
* osm_buildings.tif (Shape: (1, 1364, 1636)px, Data Type: uint8)
* osm_landuse.tif (Shape: (1, 1364, 1636)px, Data Type: float64)
* osm_water.tif (Shape: (1, 1364, 1636)px, Data Type: float64)

The dataset is available on the TUM server, but is painfully slow, so I added it to HF.

Plot:

Tagging @Jingliang-Hu as the author of the paper, if you have any other comments.