Refactor/foreign assets as thin proxy #2218

Job	Run time
canary	0s
try-runtime	0s
collator-selection	0s
forkless-update-data	0s
forkless-update-no-data	0s
node-only-update	0s
governance	0s
yarn-dev / opal	27m 3s
yarn-dev / sapphire	28m 46s
yarn-dev / quartz	35m 13s
yarn-dev / unique	27m 28s
unit-test / develop	16m 38s
xcm / Prepare execution matrix	30s
codestyle / rustfmt	17s
codestyle / yarn_eslint	28s
codestyle / clippy	2m 26s
xcm / opal	1h 20m 40s
xcm / quartz	2h 47m 20s
xcm / unique	2h 58m 13s
	9h 25m 2s

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