feat(docs/examples): Add self sponsor example for Shimmer assets #5932

Job	Run time
diff	8s
changes	7s
iota-sdk-changes	7s
license-check	0s
test-extra (self-hosted)	10m 3s
graphql-rpc	12m 24s
clippy	3m 56s
cargo-deny (advisories, licenses, bans, ...)	56s
cutting a new execution layer	47s
move-test	0s
rustfmt	7s
release-notes-check	0s
Test iota-sdk	0s
	28m 35s

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