Add functions for startup file management

[ehennestad]

Add the following functions:

• matbox.runStartup- Run a toolbox's startup file
• matbox.addStartupToMainStartup - Add a toolbox' startup file to the main startup file

[github-actions]

Test Results

 1 files   -  3   5 suites   - 15   12s ⏱️ -27s
19 tests ± 0  19 ✅ + 3  0 💤 ±0  0 ❌  - 1 
19 runs   - 57  19 ✅  - 48  0 💤 ±0  0 ❌  - 3 

Results for commit 08c8ea8. ± Comparison against base commit 64f9117.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 63 lines in your changes missing coverage. Please review.

Project coverage is 41.03%. Comparing base (64f9117) to head (08c8ea8).

Files with missing lines	Patch %	Lines
code/+matbox/addStartupToMainStartup.m	0.00%	58 Missing ⚠️
code/+matbox/runStartup.m	0.00%	4 Missing ⚠️
code/+matbox/+setup/+internal/findStartupFile.m	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #16      +/-   ##
==========================================
- Coverage   43.43%   41.03%   -2.40%     
==========================================
  Files          51       53       +2     
  Lines        1119     1182      +63     
==========================================
- Hits          486      485       -1     
- Misses        633      697      +64     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.