Dem-stitcher

Added
- The function `get_dem_tile_paths` to extract urls or local paths to dem tiles specifying bounds and dem names.
- Notebook illustrating how to create a `vrt` file using `get_dem_tile_paths`.
- Utilizes `get_dem_tile_paths` in main `stitch_dem` for easier testing.
- Caches dem tile extents loaded from compressed geojson.

Removed
- `driver` keyword in `stitch_dem`.

Added
- Included feature for extracting DEMs across datelines
- Updated merge apis with more descriptive names for more general usage
- Exceptions to determine valid extents and ensure single dateline crossing
- Added functions for dateline in `dateline.py`
- Tests for added and changed functionality.
- Integration tests for notebooks.
- Clarity about driver keyword in `stitch_dem` in readme, docstrings
- Ensure overlap of tiles is non-trivial AND polygonal (excludes point and line intersections)
- Similar check of polygonal type for window reading for better error handling
- Add `merge_nodata_value` to `merge_tile_datasets`, `merge_and_transform_dem_tiles`, and `stitch_dem` to allow for fill value of 0. As such, nodata areas within DEM tiles when converted to Ellipsoidal height will be filled in with geoid values. No other values outside of `np.nan` or `0` permitted.


Changed
- Moved functions into more logical python file including merge calls into `merge.py` and tile functions into `datasets.py`
- Renamed internal functions for greater clarity and better description of tasks
- Ensures window reading checks bounds of src raster and does intersection if required to ensure no unexpected rasterio errors. Further, raises error if no overlap.

Fixed
- Fixed tile urls for `glo*` and `srtm_v3`.
- Include directions in readme for future dem tile updates.
- Support python 3.11

Added
- Included Copernicus GLO-90 (as `glo_90`) and the missing GLO-30 tiles that are available as GLO-90 tiles as `glo_90_missing`
- Demonstration on how to fill in `glo-30` tiles that are missing with `glo-90` tiles.
- Exceptions that catch: a) no available tiles of specifed DEM as a `NoDEMCoverage` exception, b) badly specified `dem_name` as a `DEMNotSupported` exception and c) extent/bounds not of the form `xmin, ymin, xmax, ymax` as a `ValueError`
- API keyword argument `fill_in_glo_30` to fill in `glo_30` tiles that are missing, but whose corresponding `glo_90` tiles are not.
- Tests for Exceptions and added datasets
- Python 3.10 support with matrix in actions added back.

Changed
- Since AWS registry removed zip, the `glo_30` and `glo_90` geojsons have precisely the tiles that are available (had to traverse bucket)
- Notebooks to organize data have been updated

Fixed
- Fixed 33 i.e. missing `glo_30` rasters over Azerbaijan and Armenia by filling in with available `glo_90`.

Added
- Added `dst_resolution` to specify resolution of output DEM; does not alter origin; can be used to enforce square dimensions if desired
- Added tests for `rio_window.py`, `stitcher.py`, `geoid.py`, and `rio_tools.py`; including integration test which is marked
- Added notebooks related to issues 31 and 32

Changed
- Returned API to original form such that `stitch` returns tuple: `(dem_array, dem_metadata_dictionary)`
- Github actions now run on tests that are not "integration" tests, so no internet connectivity required
- Function `remove_geoid` updated to use non-resampling windowing and warns user if user does not properly set resolution buffer
- Removed gdal python bindings unrelated to rasterio
- Updated ISCE notebook

Fixed
- Fix issues 31 and 32: resampling/translation bug - do not resample unless specified in `dst_resolution`

Changed
* `dem_sticher` can now be installed in a Python 3.7 environment. Support for Python 3.7
is unlikely to remain long term as most upstream packages have dropped support for it
and [Python 3.7 End Of Life](https://endoflife.date/python) is slated for 27 Jun 2023.
* update installation instructions for consistency vis-a-vis other repos