let more random methods use an alternative source

[ChrisJefferson]

This adds the ability to use alternative sources to a variety of objects.

In particular, all the objects I regularly use, so feel confident making some examples of to test the random method is working correctly.

[codecov]

Codecov Report

Merging #1168 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #1168      +/-   ##
==========================================
+ Coverage   68.36%   68.36%   +<.01%     
==========================================
  Files         435      435              
  Lines      230662   230934     +272     
==========================================
+ Hits       157681   157884     +203     
- Misses      72981    73050      +69

Impacted Files	Coverage Δ
lib/rational.gi	64.73% <100%> (ø)	✅
lib/grpperm.gi	85.28% <100%> (ø)	✅
lib/csetgrp.gi	58.46% <100%> (+0.61%)	✅
src/gasman.c	79.48% <ø> (-4.38%)	❌
lib/csetperm.gi	87.65% <ø> (-3.71%)	❌
lib/grppcint.gi	98.64% <ø> (-0.68%)	❌
lib/stbcrand.gi	90.66% <ø> (+0.19%)	✅
lib/tietze.gi	76% <ø> (+0.73%)	✅

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