Storage example is missing from contract examples

[leighmcculloch]

We used to have a storage example in the docs, but it's not showing up anymore. Most of the examples used progressively build on the storage example. From best I can tell we don't have a simple storage example anymore.

Looking at:
https://developers.stellar.org/docs/build/smart-contracts/example-contracts

[leighmcculloch]

The example still exists in the repo here:

• https://github.com/stellar/soroban-examples/tree/main/increment