Alpine Linux agent install support

[penzoiders]

Tested Alpine Linux install script support.

Works for both x86 and ARM at 64bit (32bit misses valid binaries for mesh agent, so I've not added those among the supported systems).

Install needed packages, or ask for basic requirements.

Creates OpenRC init units instead of systemd services, works nicely as expected.

SystemD based systems works exactly as before.

[CLAassistant]

All committers have signed the CLA.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.43%. Comparing base (511bca9) to head (0d6d81c).
Report is 9 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2009      +/-   ##
===========================================
- Coverage    77.48%   77.43%   -0.06%     
===========================================
  Files          136      136              
  Lines        10030    10038       +8     
===========================================
+ Hits          7772     7773       +1     
- Misses        2258     2265       +7     

Flag	Coverage Δ
	77.43% <ø> (?)

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