fix(gateway): normalization of DNSLink inlining

[lidel]

This fix ensures inlined DNSLink identifies are normalized correctly in edge case when the value is passed to the PATH router at subdomain gateway:

With InlineDNSLink=false:

• http://localhost:8080/ipns/my-v--long-example-com → http://my.v-long.example.com.ipns.localhost:8080

With InlineDNSLink=true:

• https://dweb.link/ipns/my-v--long-example-com → https://my-v--long-example-com.ipns.dweb.link

This is quality of life improvement for users and tools who blindly copy&paste and helps with ipfs-companion edge case described in ipfs/ipfs-companion#1278 (comment).

[codecov]

Codecov Report

Merging #462 (745cee6) into main (574df96) will decrease coverage by 0.06%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #462      +/-   ##
==========================================
- Coverage   66.47%   66.42%   -0.06%     
==========================================
  Files         207      207              
  Lines       24681    24692      +11     
==========================================
- Hits        16407    16401       -6     
- Misses       6851     6863      +12     
- Partials     1423     1428       +5     

Files Changed	Coverage Δ
gateway/hostname.go	74.54% <100.00%> (+0.74%)	⬆️

... and 13 files with indirect coverage changes