Drop client fields and fieldInfo methods, use prepare instead.

[jheer]

This PR simplifies and streamlines the client lifecycle to use a single prepare call as part of client initialization. It includes the breaking change of removing the Mosaic client field and fieldInfo lifecycle methods. Instead of these methods, clients can directly call mosaic-core's queryFieldInfo within a client's prepare lifecycle method.

• Breaking: Drop client fields and fieldInfo lifecycle methods, rely solely on prepare instead. The queryFieldInfo can be used instead to lookup field info directly; it uses the same types as the removed methods.
• Update inputs and plot package to call queryFieldInfo within the client prepare method.

[domoritz]

I like this simplification. Makes sense!