allow for ip-range definition on docker mgmt net

[steiler]

As mentioned in #1364 this PR will enable ip-range assignments for docker networks.

mgmt:
  network: lab-mgmt
  bridge: testbr
  ipv4-subnet: 192.168.100.0/24
  ipv4-gw: 192.168.100.1
  ipv4-range: 192.168.100.128/25

[steiler]

I should mention that I also adjusted the ipv{4,6}_subnet to ipv{4,6}-subnet to allign with ipv{4,6}-gw, which already uses the dash notation.

[codecov]

Codecov Report

Merging #1365 (eaeae1c) into main (78a838d) will decrease coverage by 0.03%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##             main    #1365      +/-   ##
==========================================
- Coverage   20.85%   20.82%   -0.03%     
==========================================
  Files          57       57              
  Lines        6278     6286       +8     
==========================================
  Hits         1309     1309              
- Misses       4848     4856       +8     
  Partials      121      121              

Impacted Files	Coverage Δ
runtime/docker/docker.go	0.14% <0.00%> (-0.01%)	⬇️
types/types.go	0.00% <0.00%> (ø)