build: publish tree of files rather than FESMs (#18541)

* Remove now unnecessary portions of build.
* Add a compilePackageES5 method to build ES5 from sources
* Rework all package.json and rollup config files to new format
* Remove "extends" from tsconfig-build.json files and fixup compilation roots

PR Close #18541

scripts/build/map_sources.js

@@ -1,13 +0,0 @@
-
-var path = require('path');
-var sorcery = require('sorcery');
-var yargs = require('yargs');
-
-var argv = require('yargs')
-  .alias('f', 'file')
-  .argv;
-
-
-sorcery.load(argv.file).then(function(chain) {
-  chain.write();
-});