Add tailscale tools command

[kaelemc]

heavily inspired from sshx/gotty

The idea is to connect the management subnet to a tailnet and advertise that subnet onto the tailnet.

[kaelemc]

Usage:

clab tools tailscale attach --auth-key xyz

Unfortunate part is you must still approve the submet route in the tailscale web UI.. and it seems the ephemeral setting takes a random amount of time for the node to actually disappear from your tailnet.

[codecov]

Codecov Report

❌ Patch coverage is 12.85501% with 583 lines in your changes missing coverage. Please review.
✅ Project coverage is 55.36%. Comparing base (d7fb166) to head (d56d607).

Files with missing lines	Patch %	Lines
cmd/tools_tailscale.go	11.68%	578 Missing and 4 partials ⚠️
core/destroy.go	75.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2765      +/-   ##
==========================================
- Coverage   56.55%   55.36%   -1.20%     
==========================================
  Files         206      207       +1     
  Lines       23858    24522     +664     
==========================================
+ Hits        13494    13577      +83     
- Misses       9132     9709     +577     
- Partials     1232     1236       +4     

Files with missing lines	Coverage Δ
cmd/options.go	92.18% <100.00%> (+0.20%)	⬆️
cmd/tools.go	88.88% <100.00%> (+0.20%)	⬆️
core/destroy.go	59.74% <75.00%> (+0.19%)	⬆️
cmd/tools_tailscale.go	11.68% <11.68%> (ø)

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