cdn: only gzip encode known mimetypes

[joaomoreno]

When Chrome streams media from web servers while bypassing its cache, it doesn't accept gzip content encoding. We are currently hardcoding gzip encoding for all requests across our CDN. We need to only do this for known mimetypes.

[joaomoreno]

For verification:

Bad

Has Content-Encoding: gzip:

joao@speedy:~$ http -h https://main.vscode-cdn.net/stable/441438abd1ac652551dbe4d408dfcec8a499b8bf/out/vs/platform/audioCues/browser/media/error.mp3
HTTP/1.1 200 OK
Cache-Control: max-age=31536000, public
Content-Encoding: gzip
Content-Length: 12072
Content-Type: audio/mpeg
Cross-Origin-Resource-Policy: cross-origin
Date: Fri, 17 Feb 2023 08:50:01 GMT
ETag: 0x8DB0A1BF56470A0
Last-Modified: Wed, 08 Feb 2023 21:32:20 GMT
Server: Windows-Azure-Blob/1.0 Microsoft-HTTPAPI/2.0
Vary: Origin
X-Azure-Ref: 0uj/vYwAAAAA1LBR1HmcLRZbe2LzrxWuhWlJIRURHRTEzMTIAMTRhNWQ1NjMtNGE5Ny00MWI4LWFiNDUtNjQ5NzhlODI2YzEw
X-Azure-Ref-OriginShield: 0N9ztYwAAAAAA4muJ480HRYx6K/Yumn1bRlJBMjMxMDUwNDE3MDIzADE0YTVkNTYzLTRhOTctNDFiOC1hYjQ1LTY0OTc4ZTgyNmMxMA==
X-Cache: TCP_HIT
x-ms-blob-type: BlockBlob
x-ms-lease-status: unlocked
x-ms-meta-fsmode: 33204
x-ms-request-id: 23a4d88a-901e-00eb-2fcc-3c1af4000000
x-ms-version: 2009-09-19

Good

No longer has Content-Encoding: gzip:

joao@speedy:~$ http -h https://main.vscode-cdn.net/insider/71f619cbda2b051d0b083a6393b175abd1ef30ad/out/vs/platform/audioCues/browser/media/error.mp3
HTTP/1.1 200 OK
Cache-Control: max-age=31536000, public
Content-Length: 38080
Content-Type: audio/mpeg
Cross-Origin-Resource-Policy: cross-origin
Date: Fri, 17 Feb 2023 08:51:03 GMT
ETag: 0x8DB10A856D4C5BA
Last-Modified: Fri, 17 Feb 2023 05:32:20 GMT
Server: Windows-Azure-Blob/1.0 Microsoft-HTTPAPI/2.0
Vary: Origin
X-Azure-Ref: 09z/vYwAAAAAQqnx0r/5wTL47t0LxH/WtRlJBMjMxMDUwNDE4MDI5ADE0YTVkNTYzLTRhOTctNDFiOC1hYjQ1LTY0OTc4ZTgyNmMxMA==
X-Cache: TCP_MISS
x-ms-blob-type: BlockBlob
x-ms-lease-status: unlocked
x-ms-meta-fsmode: 33204
x-ms-request-id: 36c4034c-401e-00e9-60ac-42180e000000
x-ms-version: 2009-09-19