feat: allow ip prefix in x-ports

[miekg]

This allows you to specify a, portable but global compose that binds only to certain interfaces. Namely those that are contained in the prefix spec.

This should a better idea than #333

[miekg]

finally came around to actually deploy this, with the fixed I pushed:

% uc deploy -y     
Deployment plan

+ create service caddy (global)
  │   image: registry.science.ru.nl/cncz/sys/image/caddy:v0.1.14
  │
  ├── +   run container caddy on machine-lyrk
  ╰── +   run container caddy on machine-vkre

────────────────────────────
2 create · across 2 machines

[+] Deploying 6/6
 ✔ Container caddy-el2a on machine-lyrk                                   Running                                                      7.3s
   ✔ Image registry.science.ru.nl/cncz/sys/image/caddy:v0.1.14 on machine-lyrk  Pulled                                                 1.9s
 ✔ Container caddy-yntr on machine-vkre                                   Running                                                      6.5s
   ✔ Image registry.science.ru.nl/cncz/sys/image/caddy:v0.1.14 on machine-vkre  Pulled                                                 1.1s
%    
% uc ls        
NAME    MODE     REPLICAS   IMAGE                                                 ENDPOINTS
caddy   global   2          registry.science.ru.nl/cncz/sys/image/caddy:v0.1.14   (custom Caddy config)
%   
% uc ls|cat 
Connecting to ssh://test@uncloud2.vm.science.ru.nl
Connected to cluster.
NAME    MODE     REPLICAS   IMAGE                                                 ENDPOINTS
caddy   global   2          registry.science.ru.nl/cncz/sys/image/caddy:v0.1.14   (custom Caddy config)

with

    x-ports:
      - 80:80@host
      - 443:443@host
      - 443:443/udp@host
      - 131.174.88.0/24:53:53/tcp@host
      - 131.174.88.0/24:53:53/udp@host

[psviderski]

Overall looks good but please see a comment about another unhandled case when splitting by slashes. We might want to rework the entire logic to start splitting by colons first.