fix: move random utils from test_utils to aries_vcx_core, closes #1101

[xprazak2]

test_utils heavily relies on types from aries_vcx_core, so removing it as a dependency would mean remove essentially all the setup functions. The approach here is as follows:

• remove test_utils as a crate, move the code into aries_vcx_core
• add test_utils feature flag
• use aries_vcx_core with test_utils feature flag as a dev dependency where needed

[codecov-commenter]

Codecov Report

Attention: 14 lines in your changes are missing coverage. Please review.

Comparison is base (41ea29f) 0.05% compared to head (b186115) 0.05%.

❗ Current head b186115 differs from pull request most recent head 1088388. Consider uploading reports for the commit 1088388 to get more accurate results

Files	Patch %	Lines
...ries/misc/legacy/diddoc_legacy/src/aries/diddoc.rs	0.00%	4 Missing ⚠️
aries/misc/legacy/libvcx_logger/src/error.rs	0.00%	3 Missing ⚠️
aries/misc/legacy/libvcx_logger/src/lib.rs	0.00%	2 Missing ⚠️
aries/aries_vcx/src/common/credentials/encoding.rs	0.00%	1 Missing ⚠️
...ies/aries_vcx/src/handlers/out_of_band/receiver.rs	0.00%	1 Missing ⚠️
aries/aries_vcx/src/handlers/util.rs	0.00%	1 Missing ⚠️
aries/aries_vcx/src/protocols/did_exchange/mod.rs	0.00%	1 Missing ⚠️
aries/aries_vcx_core/src/test_utils/devsetup.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##            main   #1104      +/-   ##
========================================
- Coverage   0.05%   0.05%   -0.01%     
========================================
  Files        472     472              
  Lines      24109   24642     +533     
  Branches    4336    4540     +204     
========================================
  Hits          13      13              
- Misses     24095   24628     +533     
  Partials       1       1              

Flag	Coverage Δ
unittests-aries-vcx	0.05% <0.00%> (-0.01%)	⬇️

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[xprazak2]

Not needed, closing.