Cernopendata-client

* Adds support for Python 3.11 and 3.12.
* Improves `get-metadata --output-field` command by adding a new `--filter`
option allowing to output only selected field values matching desired
criteria.
* Changes container image base to Fedora 38 and slightly optimises image size.
* Drops support for Python 2.7.

* Adds support for Python 3.10.
* Improves `download-files` command to resume interrupted downloads when using
HTTP downloads with `pycurl` engine.
* Improves XRootD downloader by using vanilla XRootD package. Changes
`xrootdpyfs` to `xrootd` download engine.
* Improves `download-files` command with a new option `--download-engine` to
select `pycurl` or `requests` engines when downloading files over HTTP.
* Fixes minor issues with file index unwinding and output directory handling.

* Adds new `list-directory` command to list content of EOS directories holding
open data files.
* Adds support for Python 3.9.
* Improves `download-files` command to allow using XRootD protocol.
* Improves `download-files` command to allow using HTTPS protocol.
* Improves `download-files` command to optionally verify file integrity as soon
as files are being downloaded.
* Improves `get-file-locations` command to optionally output file sizes and
checksums.
* Improves output format colouring to better indicate notes and errors.
* Fixes minor issues and improves code coverage.

* Enriches `download-files` command to optionally download only files matching
certain name, regexp, or range count.
* Adds new `verify-files` command to verify number, size, and checksum of
downloaded files.
* Improves `get-metadata` command with respect to outputting only certain
desired metadata field values.
* Enriches user documentation.

* Initial public release.