chore: add Berty validator node in conf files

[D4ryl00]

This PR adds the Berty validator node in the config and README files for the test5 launch.

Contributors' checklist...

• Added new tests, or not needed, or not feasible
• Provided an example (e.g. screenshot) to aid review or the PR is self-explanatory
• Updated the official documentation or not needed
• No breaking changes were made, or a BREAKING CHANGE: xxx message was included in the description
• Added references to related issues and PRs
• Provided any useful hints for running manual tests

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 63.76%. Comparing base (3ab5455) to head (b8eace4).
Report is 2 commits behind head on dev/zivkovicmilos/test5-deployment.

Additional details and impacted files

@@                          Coverage Diff                           @@
##           dev/zivkovicmilos/test5-deployment    #3095      +/-   ##
======================================================================
+ Coverage                               63.74%   63.76%   +0.01%     
======================================================================
  Files                                     548      548              
  Lines                                   78666    78681      +15     
======================================================================
+ Hits                                    50146    50169      +23     
+ Misses                                  25136    25130       -6     
+ Partials                                 3384     3382       -2     

Flag	Coverage Δ
contribs/gnodev	61.16% <ø> (+0.62%)	⬆️
contribs/gnofaucet	15.77% <ø> (+0.94%)	⬆️
gno.land	73.62% <ø> (ø)
gnovm	67.92% <ø> (+<0.01%)	⬆️
misc/genstd	79.72% <ø> (ø)
tm2	62.41% <ø> (+0.04%)	⬆️

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