Improve environment reporting

[amotl]

Is your feature request related to a problem? Please describe.
For improving the possibilities to get an idea of the user's environment, Wetterdienst should offer some feature to report about respective details.

Describe the solution you'd like
I would like to see this feature implemented similar to Pandas' pd.show_versions() [1] or requests' python -m requests.help [2].

[1] https://github.com/pandas-dev/pandas/blob/master/.github/ISSUE_TEMPLATE/bug_report.md#output-of-pdshow_versions
[2] https://github.com/psf/requests/blob/master/.github/ISSUE_TEMPLATE/Bug_report.md#system-information

This might also be conveniently provided through a CLI invocation like wetterdienst info.

Further suggestions
Please also include the path to the cache directory, as it has been tried at

wetterdienst/wetterdienst/util/cache.py

Line 22 in 5c8f589

log.info("Cache directory is %s", cache_dir)

but doesn't quite work. This somehow relates to all the dbmfile-cache issues summarized within #243 in order to at least give the user something where she will be able to deduce the cache directory from in order to be able to purge it.