Refactor/foreign assets as thin proxy #2211

Job	Run time
canary	0s
forkless-update-data	0s
collator-selection	0s
forkless-update-no-data	0s
try-runtime	0s
governance	0s
node-only-update	0s
unit-test / develop	12m 25s
xcm / Prepare execution matrix	26s
yarn-dev / opal	31m 42s
yarn-dev / sapphire	40m 46s
yarn-dev / quartz	40m 30s
yarn-dev / unique	26m 57s
codestyle / clippy	2m 29s
codestyle / rustfmt	14s
codestyle / yarn_eslint	25s
xcm / opal	1h 20m 29s
xcm / quartz	1h 52m 4s
xcm / unique	1h 52m 8s
	7h 40m 35s

Provide feedback