feat: support ignore to ignore scanned files

[pi0]

🔗 Linked issue

Resolves #843

Related: nuxt/nuxt#13427, #945

❓ Type of change

• 📖 Documentation (updates to the documentation or readme)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ New feature (a non-breaking change that adds functionality)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

This PR supports ignore: string[] option in order to specify ignore patterns for scanning /plugins, /middleware, /routes and /api from all layers. The scan.ts has been almost rewritten to be prepared for this. Supporting public dir ignore in #945 after this.

📝 Checklist

• I have linked an issue or discussion.
• I have updated the documentation accordingly.

[codecov]

Codecov Report

Merging #1430 (3ff5c47) into main (fd9a9ee) will increase coverage by 0.30%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #1430      +/-   ##
==========================================
+ Coverage   76.47%   76.77%   +0.30%     
==========================================
  Files          71       71              
  Lines        7323     7323              
  Branches      724      725       +1     
==========================================
+ Hits         5600     5622      +22     
+ Misses       1722     1699      -23     
- Partials        1        2       +1     

Impacted Files	Coverage Δ
src/options.ts	94.87% <100.00%> (+0.01%)	⬆️
src/scan.ts	100.00% <100.00%> (ø)
src/types/nitro.ts	100.00% <100.00%> (ø)

... and 3 files with indirect coverage changes