* Store static data as top-level metadata of the file

* `data_write.SliceData` -> `utils.file_formats.SliceData`
* Refactored the general HDF5 file format:
   - Top level "metadata" group
   - All data stored as `Dataset`, with `"description"` metadata attached
   - File-level metadata is hard-linked within each record group to the top-level "metadata" group entry

* Added labels for dimensions of vector fields in the data files, to aid in data interpretation and usage.
* Created HDF5Writer class to handle turning SliceData dataclass into the correct types for writing to Borealis HDF5 files.
* Removed ability to write JSON files
* Started refactoring DataWrite.output_data() to remove the internal functions
* DataWrite.__init__() now instantiates sockets internally (avoids passing sockets to threads, which is explicitly recommended against by zmq documentation)
* Functionality to send rawacf record to realtime is now internal to write_correlations() function
* Added `rx_main_phases` and `rx_intf_phases` fields
* Removed `--file-type` option to data_write.py script (only hdf5 supported)
* Replaced useless `assert` statement (ignored when script run with `-O` flag, which `steamed_hams.py` uses for release mode)

…vious commit.

* Added support for writing rawacf files directly as DMAP
* Added dimension scales to certain fields for HDF5 files. These are datasets associated with a dimension of another dataset, e.g. associating the `sqn_timestamps` with the "sequence" dimension of `data`.
* Added units metadata for fields in HDF5 files.
* Added "rawacf_format" field to config files, specifying the default format to use when writing rawacf files.
* Added support to overwrite the rawacf format files are written with the "--rawacf-format" argument to steamed_hams.py
* Added `darn-dmap` as a dependency, and fixed numpy and pydarnio versions.

* New `antennas` field which holds all antenna information
   - `main_locations`: {index: [x, y, z]} for each main antenna
   - `intf_locations`: {index: [x, y, z]} for each intf antenna
   - `main_antenna_count`: number of main array antennas
   - `intf_antenna_count`: number of intf array antennas
   - `main_antenna_spacing`: uniform spacing between main-array antennas
   - `intf_antenna_spacing`: uniform spacing between intf-array antennas
   - `standard_positions`: flag indicating whether array antennas follow the standard linear configuration. If so, verifies that positions are parallel to x-axis and equally spaced by [main|intf]_antenna_spacing
* Added tests for the new fields
* Updated config files for each site

* Each type (antennas_iq, bfiq, etc.) has its own data field (antennas_iq_data, bfiq_data, etc.)
* `antenna_locations` field added containing [x, y, z] locations of each antenna
* `antenna_arrays` field added for bfiq files containing descriptors for the array dimension of the data (e.g. ["main", "intf"]
* `required` added to metadata, indicating whether it is an error for a field to be missing or not.
* `data` field removed
* `[main|intf]_antenna_count` fields removed
* `lags` field renamed to `lag_pulses`
* `num_ranges` and `num_samps` fields removed
* `range_gates` field added, simply an array of the range gates for the file (e.g. 0-74)
* `rx_antennas`, ``rx_main_antennas`, `rx_intf_antennas`, and `tx_antennas` fields added, giving indices into `antenna_locations` of the antennas used for the experiment
* `station_location` field added, giving lat, lon, altitude of the radar
* Refactored `get_phase_shift()` in `signals.py` to use the antenna positions and interferometer array offsets for beamforming

* also refactored some variable names for simplicity

…e fields

* Created script file_docs_builder.py to generate .rst files for each file type
* Changed file name when writing DMAP files directly (ensuring slice_id is written as a letter instead of a number)

…ata, bfiq_data, rawrf_data final dimension.

* Given as an array of ints, representing the time of measurement relative to the first pulse in the sequence. Microseconds.

* `tests/simulators/steamed_sham.py` will call a simulator instead of usrp_driver.cpp
* `tests/simulators/driver_sim.py` mocks usrp_driver.cpp, generating
  noise instead of data (and not currently adding the pulse data to the
noise)

* Updated record name format to use hyphens, like `YYYYMMDD-HHMM-SS.fffff`
* Removed `dim_labels` from `lag_pulses` field
* Correctly format SliceData object as DMAP
* Use new pydarnio functions for converting rawacf records
* Fix dmap filename convention
* Serve data for all slices to realtime from data_write
* Replaced test data for realtime sim with single-record dmap

… xarray

* pyDARNio implementation of array-structured fields being added in parallel to this branch. This implementation will only allow in-memory array-structuring, and will not support writing of array-structured data files.

… into new_data_format

* Pulling in the merge conflict commit Draven added