Ledger live and desktop wallet

[pablozsc]

Changes

• removed Virtual Hive node, added grpc.mainnet.concordium.software instead
• For users who have previously installed the Concordium app on Ledger Live by enabling Developer mode, the process for updating the app is described.

Checklist

• My code follows the style of this project.
• The code compiles without warnings.
• I have performed a self-review of the changes.
• I have documented my code, in particular the intent of the
  hard-to-understand areas.

By submitting the contribution I accept the terms and conditions of the
Contributor License Agreement v1.0

• link: https://developers.concordium.com/CLAs/Contributor-License-Agreement-v1.0.pdf

• I accept the above linked CLA.

[pablozsc]

Before doing a merge PR, I suggest waiting until the Concordium app is available without developer mode enabled, so that we can test everything that is written.

Only then do Merge.

[dragosgd]

LGTM