Update trust for other nodes

[buckyroberts]

Create the following endpoints to allow the editing of trust for Banks and Validators:

• PATCH /banks/<node_identifier>
• PATCH /validators/<node_identifier>

using the is_self() decorator.

• https://github.com/thenewboston-developers/Bank/blob/master/v1/decorators/nodes.py#L56

Note: trust is the only field that should be editable from the API. All other fields are written directly from the target nodes /config data.