Improve TS CFG DSL

[Lipen]

This PR improves CFG DSL by adding boolean/integer/string constants and CustomValue (for arbitrary EtsEntity), and also by refining if/elseif/else stmt builders.

[codecov]

Codecov Report

❌ Patch coverage is 26.90058% with 125 lines in your changes missing coverage. Please review.
✅ Project coverage is 69.32%. Comparing base (5acbadf) to head (58343b2).
⚠️ Report is 4 commits behind head on neo.

Files with missing lines	Patch %	Lines
...ain/kotlin/org/jacodb/ets/utils/BlockCfgBuilder.kt	23.95%	66 Missing and 7 partials ⚠️
...c/main/kotlin/org/jacodb/ets/dsl/ProgramBuilder.kt	15.90%	37 Missing ⚠️
...codb-ets/src/main/kotlin/org/jacodb/ets/dsl/DSL.kt	0.00%	11 Missing ⚠️
...odb-ets/src/main/kotlin/org/jacodb/ets/dsl/Expr.kt	80.00%	4 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##                neo     #340      +/-   ##
============================================
- Coverage     69.53%   69.32%   -0.21%     
+ Complexity     2492     2491       -1     
============================================
  Files           275      275              
  Lines         15646    15715      +69     
  Branches       2354     2361       +7     
============================================
+ Hits          10879    10894      +15     
- Misses         3837     3885      +48     
- Partials        930      936       +6     

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[github-actions]

Test Results

  215 files  ±0    215 suites  ±0   15m 54s ⏱️ +3s
  711 tests ±0    699 ✅ ±0  12 💤 ±0  0 ❌ ±0 
1 977 runs  ±0  1 927 ✅ ±0  50 💤 ±0  0 ❌ ±0 

Results for commit 58343b2. ± Comparison against base commit 5acbadf.