feat: compress some content types

[ghost]

Store gzip content encodings of assets with media types, if the compressed encoding is smaller than the source contents:

• text/*
• */javascript
• */html

Uploading assets to asset canister...
  /index.js 1/1 (320675 bytes)
  /index.js (gzip) 1/1 (103964 bytes)
  /index.js.map 1/1 (1026607 bytes)
  /index.js.map (gzip) 1/1 (266929 bytes)

Implements https://github.com/dfinity/dx-triage/issues/117

[hansl]

Can you use caseInsentiveCharCompare too on the checking for header? Not blocking, but I think it might improve readability;

Suggested change

	let k = Text.map(header.0, Prim.charToUpper);
	let v = header.1;
	if (k == "ACCEPT-ENCODING") {
	if (Text.compareWith(header.0, "Accept-Encoding", caseInsensitiveCharCompare)) {
	let v = header.1;

[ghost]

I meant to remove caseInsensitiveTextEqual or at least leave a comment about it, because Text.compareWith(a,b,cmp) currently has a bug where it ignores the cmp parameter and instead always uses Char.compare

[hansl]

LGTM. One non blocking comment that I'll leave to you.