To limit the exposure of the private `LOCALE_DATA` from outside
`@angular/core` this commit exposes private functions in the core
to hide the internal structures better.
* The `registerLocaleData()` implementation has moved from
`@angular/common` to `@angular/core`. A stub that delegates to
core has been left in common for backward compatibility.
* A new `ɵunregisterLocaleData()` function has been provided,
which is particularly useful in tests to clear out registered locales
to prevent subsequent tests from being affected.
* A private export of `ɵregisterLocaleData()` has been removed
from `@angular/common`. This was not being used and is accessible
via `@angular/core` anyway.
PR Close#33523
* 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