TxBuilder: Remove hard dependency to WellKnown keys

[Geod24]

The last step missing to allow the TxBuilder to be truly independent from the Well-Known keys, yet offer a similar API.

[codecov[bot]]

Codecov Report

Merging #3238 (e3ec223) into v0.x.x (22ad709) will decrease coverage by 58.87%. The diff coverage is 0.00%.

@@             Coverage Diff             @@
##           v0.x.x    #3238       +/-   ##
===========================================
- Coverage   88.36%   29.48%   -58.88%     
===========================================
  Files         166      264       +98     
  Lines       17065    27050     +9985     
===========================================
- Hits        15080     7977     -7103     
- Misses       1985    19073    +17088     

Flag	Coverage Δ
integration	29.48% <0.00%> (-4.87%)	:arrow_down:
unittests	?

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
source/agora/utils/PrettyPrinter.d	77.94% <ø> (-21.25%)	:arrow_down:
source/agora/utils/Test.d	0.00% <0.00%> (-92.46%)	:arrow_down:
source/agora/utils/TxBuilder.d	0.00% <0.00%> (-98.58%)	:arrow_down:
source/agora/script/Stack.d	0.00% <0.00%> (-100.00%)	:arrow_down:
source/agora/flash/Invoice.d	0.00% <0.00%> (-100.00%)	:arrow_down:
source/agora/flash/Network.d	0.00% <0.00%> (-100.00%)	:arrow_down:
source/agora/flash/Scripts.d	0.00% <0.00%> (-100.00%)	:arrow_down:
source/agora/script/Script.d	0.00% <0.00%> (-100.00%)	:arrow_down:
source/agora/utils/Backoff.d	0.00% <0.00%> (-100.00%)	:arrow_down:
source/agora/script/Opcodes.d	0.00% <0.00%> (-100.00%)	:arrow_down:
... and 310 more

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[mkykadir]

Moved to #3256