Add guides for using delegation scopes

[alexandratran]

Delegations now require users to define a delegation scope. Add how-to guides on how to define the various types of scopes:

• Spending limit scopes
• Function call scope
• Ownership transfer scope

[alexandratran]

Follow up tasks:

• Add parameter lists in the delegation scopes reference.
• Update the createDelegation and createOpenDelegation methods in the API reference to include a required scope property.
• Update the Create a delegation step in the Execute on a smart account's behalf guide to include mandatory scopes.
• Update the Delegation concept page to explain delegation scopes. Perhaps scopes can be explained in the Caveat enforcers concept page as well?