feat: normalize route options and shortcuts

[pi0]

Context: #538

By normalizing route options, we can support more shortcuts and also avoid duplicate logic per vendor for native support.

This PR normalizes 3 shortcuts:

• cors => converted to headers
• swr / static => converted to (new) cache options (rework of feat: use CachedEventHandler options in nitro routes config #443)
• [redirect is normalized]

Also fixes some issues with netlify and vercel generated rules

[codecov]

Codecov Report

Merging #583 (014f5e0) into main (d5fa627) will increase coverage by 0.09%.
The diff coverage is 90.52%.

❗ Current head 014f5e0 differs from pull request most recent head dc97adc. Consider uploading reports for the commit dc97adc to get more accurate results

@@ Coverage Diff @@## main #583 +/- ##
==========================================
+ Coverage 66.01% 66.11% +0.09% 
==========================================
Files 55 55 Lines 4061 4099 +38 Branches 439 439 ==========================================
+ Hits 2681 2710 +29 - Misses 1376 1385 +9 
Partials 4 4 

Impacted Files	Coverage Δ
src/options.ts	85.07% <83.72%> (-0.33%)	⬇️
src/presets/netlify.ts	53.67% <92.30%> (-2.67%)	⬇️
src/presets/vercel.ts	64.46% <94.11%> (-3.72%)	⬇️
src/types/nitro.ts	100.00% <100.00%> (ø)

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