Carry resolver docs and default value strategies in the official plugins

[lorisleiva]

This PR lets the official plugins keep two pieces of v1 information that renderers need when upgrading resolvers and extra arguments:

• The codama.resolver payload gains an optional docs field describing the resolver: { name, dependsOn?, docs? }.
• The codama.extraArgument payload gains an optional defaultValueStrategy, as for struct fields: { identifier, type, defaultValue?, defaultValueStrategy?, docs? }.
• structFieldTypeNode.defaultValueStrategy now also applies when a codama.resolver plugin resolves the field. For example, omitted keeps a resolved field out of generated inputs, as renderers already do for v1 resolver defaults.

structFieldTypeNode({
    identifier: 'tags',
    type: integerTypeNode('u8'),
    defaultValueStrategy: 'omitted',
    plugins: [pluginNode('codama.resolver', { payload: { name: 'resolveTags', docs: 'Derives tags from the name.' } })],
});