implement "borg version", fixes #7829

[ThomasWaldmann]

Since long, we have borg --version to display the borg (client) version string in its very detailed form provided by setuptools_scm, e.g.:

borg 1.4.0.dev119+gc7cef548.d20240119

Now there is an additional new command "borg version ", which shows the client / server version, e.g.:

1.4.0a / 1.2.7

If a local repo is given, the client code directly accesses the repository, thus we show the client version also as the server version.

If a remote repo is given (e.g. ssh:), the remote borg is queried and its version is displayed as the server version.

Due to the version tuple format used in borg client/server negotiation, only a simplified version is displayed (as provided by borg.version.format_version).

[codecov-commenter]

Codecov Report

Attention: 7 lines in your changes are missing coverage. Please review.

Comparison is base (319441e) 82.56% compared to head (fe3cda8) 82.48%.
Report is 2 commits behind head on 1.4-maint.

❗ Current head fe3cda8 differs from pull request most recent head 8d72927. Consider uploading reports for the commit 8d72927 to get more accurate results

Files	Patch %	Lines
src/borg/archiver.py	41.66%	7 Missing ⚠️

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Additional details and impacted files

@@              Coverage Diff              @@
##           1.4-maint    #8053      +/-   ##
=============================================
- Coverage      82.56%   82.48%   -0.08%     
=============================================
  Files             38       38              
  Lines          10913    10925      +12     
  Branches        2084     2086       +2     
=============================================
+ Hits            9010     9012       +2     
- Misses          1345     1355      +10     
  Partials         558      558              

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