Replace node-sass with sass in openecomp-ui

Replace node-sass with sass in openecomp-ui

- node-sass is deprecated [0] and the project recommends
  migrating to Dart Sass [1]
- sass is stricter than node-sass and disallows the usage of
  the /deep/ shadow dom selector
- /deep/ is defined in a version of onap-ui-common [2]  that is newer
  than what is contained in the corresponding gerrit repo, thus
  a manual patch of the artifact is required

[0] https://www.npmjs.com/package/node-sass
[1] https://sass-lang.com/dart-sass/
[2] https://gerrit.onap.org/r/admin/repos/sdc/onap-ui-common

Issue-ID: SDC-4811
Change-Id: Ia0f7e9142e09bef3eb9f11a5aae4bb41c20d9844
Signed-off-by: Fiete Ostkamp <fiete.ostkamp@telekom.de>