Feat: Improve commitment sharing process

[gianalarcon]

Currently when creating a new multisig wallet, User B have to generate a commitment and sent it to user A somehow, by telegram or any other app.

We can change it and improve this flow like

• User A can send an invitation to user B.
• User B fill the invitation generating his commitment.
• User A will get the commitment direct into the App.

With this we avoid that user A needs to copy and paste commitment.