[Playground] Regenerate built-in wallet button

[ukorvl]

We want to have "Regenerate wallet" button in the playground built-in wallet that will allow to reset private key, stored in the browser localStorage and generate and deploy new wallet smart account.

Motivation:

• if we dropped data (which at the current stage happens) the wallet contract is gonna be lost, meanwhile browser wallet is gonna know nothing about it and produce errors on startup
• it is useful for development as well, when you want to start from scratch

Design is not implemented yet. What we have is an example from wallet extension design a link to Figma.

[khannanov-nil]

proceeding with this issue