Additional charcteristics

[samuelmr]

I suggest adding the following characteristics:

• holderCapability: Can hold and present digital credentials
• issuerCapability: Can issue digital credentials
• verifierCapability: Can verify digital credentials
• api: Can be integrated into other systems via an application programming interface
• webApp: address of a cloud service agent (e.g. https://www.blockcerts.org/, https://certs.dock.io/, https://connect.trinsic.cloud, https://demo.lissi.id/, https://wallet.essif.sk/, https://wallet.walt.id/) that cannot be downloaded from app stores

[samuelmr]

The download section doesn´t work well for cloud wallets...

[maaikevanleuken]

Flatten structure, add link for cloud wallets, add download(s) for phone wallets.

[maaikevanleuken]

Let's add all of these.