rAHNextract v0.98

Breaking changes

AHN1-AHN3 is currently not supported to be used. Please change it to 'AHN' to always use the latest version made available by PDOK. Currently that is AHN4.
The default extraction method to receive the AHN elevation is changed to 'simple' (nearest) instead of bilinear. Please see this article that explains the difference.
In this release downloading point clouds is not supported.
It is now possible to retrieve AHN elevation data at exact intersection points of 2 or more AHN sheets.

AHN4 is the latest full AHN version made available by PDOK. This release now supports this AHN version.
in ahn_area() introduced the ability to only download AHN sheets using the sheets parameter.
Introduced the function ahn_sheets_info() to retrieve information about the AHN sheets and which URLs are used for download.
Improved the code so that always rectified grid is used, or else give warnings.
Removed the ability to use older AHN versions (AHN1-AHN3). It is in the planning to reintroduce this in a future release.
Removed the ability to download point cloud data from the AHN. This will possibly be reintroduced in a future release.
Adjusted URLs so that AHN datasets hosted by PDOK can be retrieved again.
The code now looks at source URLs from data frames instead of hard coded references in the code.
Efficient checks are built in to see if the AHN version called is currently supported.
Reorganised code and removed deprecated/unsupported functions.
Removed all dependencies of the deprecated 'rgdal' package. 'Terra' package is now used instead of 'raster'.
Updated all the dependent package to the the latest versions.
improved R syntax throughout the whole code.