[projmgr] Add $TargetSet$ access sequence for better tmpdir separation

[brondani]

Address ground issue reported in Open-CMSIS-Pack/vscode-cmsis-solution#102

Enable $TargetType$ and $TargetSet$ access sequences resolution in tmpdir customization:

  output-dirs:
    tmpdir: tmp/$TargetType$/$TargetSet$

This allows switching target-set back and forth without triggering rebuilds.

[github-actions]

Test Results

  7 files   53 suites   5m 56s ⏱️
185 tests 168 ✅ 17 💤 0 ❌
692 runs  624 ✅ 68 💤 0 ❌

Results for commit 1020297.

♻️ This comment has been updated with latest results.

[codecov]

Codecov Report

❌ Patch coverage is 77.77778% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 64.72%. Comparing base (d2240ff) to head (1020297).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
tools/projmgr/src/ProjMgrWorker.cpp	66.66%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2415   +/-   ##
=======================================
  Coverage   64.72%   64.72%           
=======================================
  Files         145      145           
  Lines       26137    26141    +4     
  Branches    15774    15777    +3     
=======================================
+ Hits        16918    16921    +3     
  Misses       7066     7066           
- Partials     2153     2154    +1     

Flag	Coverage Δ
buildmgr-cov	79.87% <ø> (ø)
packchk-cov	69.73% <ø> (ø)
projmgr-cov	87.76% <77.77%> (-0.01%)	⬇️

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

Files with missing lines	Coverage Δ
tools/projmgr/src/ProjMgr.cpp	80.85% <100.00%> (ø)
tools/projmgr/src/ProjMgrCbuildIdx.cpp	96.12% <100.00%> (+0.02%)	⬆️
tools/projmgr/src/ProjMgrWorker.cpp	88.20% <66.66%> (-0.02%)	⬇️

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