Check public STUN servers

In !2 (merged) I found out there are some issues (STUN server did not respond). The list in the code is outdated, e.g

pea@peabox:bootstrap go test -count=1 -v ./... -run TestGeolocatation
=== RUN   TestGeolocatation
1:23PM INF TEST_MENSHEN_HOST env (hostname of menshen) is not set. Using localhost as default
1:23PM INF TEST_MENSHEN_PORT env (port of menshen) env is not set. Using 8443 as default
1:23PM INF TEST_MENSHEN_TLS env (connect via tls to menshen) is not set. Using default false. Set TEST_MENSHEN_TLS=1 to connect vial TLS
1:23PM DBG Disabling DNS over HTTP (not using SSL)
1:23PM TRC Getting country code
1:23PM TRC Trying to get current ip address using STUN servers
1:23PM TRC Trying STUN server server=stun3.l.google.com:3478
Overwriting stun server in tunnel-telemetry: stun1.l.google.com:3478
1:23PM WRN Could not get ip using STUN server error="transaction is timed out" server=stun3.l.google.com:3478
1:23PM TRC Trying STUN server server=stun.ekiga.net:3478
Overwriting stun server in tunnel-telemetry: stun1.l.google.com:3478
1:23PM WRN Could not get ip using STUN server error="transaction is timed out" server=stun.ekiga.net:3478
1:23PM TRC Trying STUN server server=209.105.241.31:3478
Overwriting stun server in tunnel-telemetry: stun1.l.google.com:3478
1:23PM WRN Could not get ip using STUN server error="transaction is timed out" server=209.105.241.31:3478
1:23PM TRC Trying STUN server server=stun.nextcloud.com:443
Overwriting stun server in tunnel-telemetry: stun1.l.google.com:3478
1:23PM WRN Could not get ip using STUN server error="transaction is timed out" server=stun.nextcloud.com:443
1:23PM TRC Trying STUN server server=3.132.228.249:3478
Overwriting stun server in tunnel-telemetry: stun1.l.google.com:3478
1:23PM WRN Could not get ip using STUN server error="transaction is timed out" server=3.132.228.249:3478
1:23PM TRC Trying STUN server server=193.22.17.97:3478
Overwriting stun server in tunnel-telemetry: stun1.l.google.com:3478
1:24PM WRN Could not get ip using STUN server error="transaction is timed out" server=193.22.17.97:3478
1:24PM TRC Trying STUN server server=stun.xten.com:3478
Overwriting stun server in tunnel-telemetry: stun1.l.google.com:3478
^Csignal: interrupt
FAIL    0xacab.org/leap/bitmask-core/pkg/bootstrap      67.930s

stun1.l.google.com:3478 does not work anymore. But stun1.l.google.com:19302 works.