* DEV: Move `Discourse.getURL` and related functions to a module
* DEV: Remove `Discourse.getURL` and `Discourse.getURLWithCDN`
* FIX: `get-url` is required for server side code
* DEV: Deprecate `BaseUri` too.
This reverts commit 20780a1eee.
* SECURITY: re-adds accidentally reverted commit:
03d26cd6: ensure embed_url contains valid http(s) uri
* when the merge commit e62a85cf was reverted, git chose the 2660c2e2 parent to land on
instead of the 03d26cd6 parent (which contains security fixes)
