Nexusformat

* Allows soft links to use relative paths. For backward compatibility, relative paths with respect to the NXroot object are checked if a path is invalid.
* Improves the compatibility of the written root attributes to the NeXus definitions.
* Ensures that root attributes are written correctly when using `nxopen` as a context manager.
* Adds a `get` function to the attribute dictionary.

* Updates NumPy calls to be compatible with NumPy v2.0.0, released on June 16.

* Adds the parent group to the NXdata group returned by the `weighted_data` function. This helps with labelling plots in NeXpy.

* Updates the NeXus base classes following the release of NeXus v2024.02.

* Opens files as read-only when initializing `NXFile` instances, in order to prevent `h5py` exceptions when other applications, *e.g.*, those not using the `nexusformat` file-locking mechanism, have already opened the file. If `write` mode is requested, it is applied when performing I/O operations.
* Calculates the size of NXfield arrays as 64-bit integers to prevent overflow issues when the NumPy `prod` function uses 32-bit integers. On some systems, this has caused large arrays to be loaded into memory inadvertently.

* Ensures lock files are released if opening a file with h5py triggers an exception.
* Fixes an incompatibility with tab completion and call tips in IPython 8.12.
* Allows additional arguments when coercing NXfields to NumPy arrays.
* Fixes docstrings.