ref: delete unreachable upstream-fetcher modules

Stacked on the modifications PR. Now that no live code path references
the per-package fetchers, the shared HTTP/parsing helpers, the
in-process normalizer, or the example template, delete them. Pure
deletion — no behavior change.

- ~93 per-package <pkg>/releases.js fetcher modules.
- _common/{brew,fetcher,git-tag,gitea,github,github-source,
  githubish,githubish-source}.js shared HTTP/parsing helpers.
- _webi/normalize.js in-process normalization layer (cache files
  arrive normalized from webicached).
- _example/releases.js fetcher template for new packages.

The Go cache daemon (webicached) is now the sole producer of release
metadata; the Node process never makes an upstream request.

zig/releases.js

@@ -1,117 +0,0 @@
-'use strict';
-
-let Fetcher = require('../_common/fetcher.js');
-
-let NON_BUILDS = ['bootstrap', 'src'];
-let ODDITIES = NON_BUILDS.concat(['armv6kz-linux']);
-
-/**
- * @typedef BuildInfo
- * @prop {String} version
- * @prop {String} [_version]
- * @prop {String} [arch]
- * @prop {String} channel
- * @prop {String} date
- * @prop {String} download
- * @prop {String} [ext]
- * @prop {String} [_filename]
- * @prop {String} [hash]
- * @prop {String} [libc]
- * @prop {Boolean} [lts]
- * @prop {String} [size]
- * @prop {String} os
- */
-
-module.exports = async function () {
-  let resp;
-  try {
-    let url = 'https://ziglang.org/download/index.json';
-    resp = await Fetcher.fetch(url, {
-      headers: { Accept: 'application/json' },
-    });
-  } catch (e) {
-    /** @type {Error & { code: string, response: { status: number, body: string } }} */ //@ts-expect-error
-    let err = e;
-    if (err.code === 'E_FETCH_RELEASES') {
-      err.message = `failed to fetch 'zig' release data: ${err.response.status} ${err.response.body}`;
-    }
-    throw e;
-  }
-  let versions = JSON.parse(resp.body);
-
-  /** @type {Array<BuildInfo>} */
-  let releases = [];
-  let refs = Object.keys(versions);
-  for (let ref of refs) {
-    let pkgs = versions[ref];
-    let version = pkgs.version || ref;
-
-    // "platform" = arch + os combo
-    let platforms = Object.keys(pkgs);
-    for (let platform of platforms) {
-      let pkg = pkgs[platform];
-
-      // don't grab 'date' or 'notes', which are (confusingly)
-      // at the same level as platform releases
-      let isNotPackage = !pkg || 'object' !== typeof pkg || !pkg.tarball;
-      if (isNotPackage) {
-        continue;
-      }
-
-      let isOdd = ODDITIES.includes(platform);
-      if (isOdd) {
-        continue;
-      }
-
-      // Ex: aarch64-macos => ['aarch64', 'macos']
-      let parts = platform.split('-');
-      //let arch = parts[0];
-      let os = parts[1];
-      if (parts.length > 2) {
-        console.warn(`unexpected platform name with multiple '-': ${platform}`);
-        continue;
-      }
-
-      let p = {
-        version: version,
-        date: pkgs.date,
-        channel: 'stable',
-        // linux, macos, windows
-        os: os,
-        // TODO map explicitly (rather than normalization auto-detect)
-        //arch: arch,
-        download: pkg.tarball,
-        hash: pkg.shasum,
-        size: pkg.size,
-        // TODO docs + release notes?
-        //docs: 'https://ziglang.org/documentation/0.9.1/',
-        //stdDocs: 'https://ziglang.org/documentation/0.9.1/std/',
-        //notes: 'https://ziglang.org/download/0.9.1/release-notes.html'
-      };
-
-      // Mark branches or tags as beta (for now)
-      // Ex: 'master'
-      // Also mark prereleases (with build tags) as beta
-      // Ex: 0.10.0-dev.1606+97a53bb8a
-      let isNotStable = !/\./.test(ref) || /\+|-/.test(p.version);
-      if (isNotStable) {
-        p.channel = 'beta';
-      }
-
-      releases.push(p);
-    }
-  }
-
-  return {
-    releases: releases,
-  };
-};
-
-if (module === require.main) {
-  module.exports().then(function (all) {
-    all = require('../_webi/normalize.js')(all);
-    // just select the first 5 for demonstration
-    all.releases = all.releases.slice(0, 5);
-    console.info(JSON.stringify(all, null, 2));
-  });
-}