Issue #2770983 by tstoeckler, rjacobs: Fetch definitions remotely and

CHANGELOG.txt

config/install/libraries.settings.yml

config/schema/libraries.schema.yml

libraries.install

libraries.services.yml

src/Config/LibrariesConfigSubscriber.php

src/ExternalLibrary/Definition/ChainDefinitionDiscovery.php

src/ExternalLibrary/Definition/FileDefinitionDiscovery.php

...xternalLibrary/Definition/FileDefinitionDiscoveryBase.php

src/ExternalLibrary/Definition/GuzzleDefinitionDiscovery.php

...brary/Definition/WritableDefinitionDiscoveryInterface.php

...nalLibrary/Definition/WritableFileDefinitionDiscovery.php

src/LibrariesServiceProvider.php

src/StreamWrapper/LibraryDefinitionsStream.php

tests/library_definitions/test_asset_library.json

tests/library_definitions/test_asset_multiple_library.json

tests/library_definitions/test_php_file_library.json

...ternalLibrary/Definition/ChainDefinitionDiscoveryTest.php

tests/src/Kernel/LibraryTypeKernelTestBase.php