[assets] configurable URL for static resources (#7911)

[assets] configurable URL for static resources (#7911)

* static url

* add cors support for static resources

* [assets] work on the migration to configurable url for assets

Signed-off-by: Jakob Ackermann <das7pad@outlook.com>
* [misc] fix whitespace

Signed-off-by: Jakob Ackermann <das7pad@outlook.com>
* [assets] fix the loading of the manifest.json

It is generated dynamically, and as such can not be served by the cdn.

Signed-off-by: Jakob Ackermann <das7pad@outlook.com>
* Revert "add cors support for static resources"

This reverts commit 42f964fd181dbb8b139808b9be623470d4f0e40f

Signed-off-by: Jakob Ackermann <das7pad@outlook.com>
* [docs] add the STATIC_URL_PREFIX option

Signed-off-by: Jakob Ackermann <das7pad@outlook.com>
* [docs] reverse-proxy: nginx: add two setups for STATIC_URL_PREFIX

Signed-off-by: Jakob Ackermann <das7pad@outlook.com>
* [assets] migrate the url of a new asset to the static url prefix

REF: f2a3abc683ad4b2177b7c7c6160a2c0b4316120a
Signed-off-by: Jakob Ackermann <das7pad@outlook.com>