Takes a serde config and returns the var for its
:serde-keyword key.

Takes a serde config and loads the schema from the classpath.

Returns a function of arity one which takes a serde config map and
replaces (resolves) it with the implementation for the serde. The
config map consists of a :serde-keyword key, and optionally, keys to
specify the schema or schema filename and whether the serde will be
used for an Avro key. The options are extra arguments which may be
needed to create the serde, e.g, the schema registry URL.

Options:
schema-registry-url - The URL for the schema registry
type-registry - A mapping per jackdaw.serdes.avro/+base-schema-type-registry+>

These are only needed for the Confluent Avro serde, and even then
only the schema registry URL is required.