Create a documentation for all existing Pallad features

[mrcnk]

Acceptance Criteria:

• [ ] Onboarding process is documented.
• [ ] Send Mina flow is documented.
• [ ] Receive Mina explains how to receive and top up a wallet.
• [ ] Staking is documented.
• [ ] Address Book is documented.
• [ ] Settings are documented.
• [ ] Network switching is documented.
• [ ] Necessary docs are created in https://github.com/palladians/pallad-website2. Directory: src/content/docs/docs.