Allow customization of netty http client mapper

[yawkat]

Issue description

Right now it is impossible to customize the serializer used by the netty http client. It is a static field in OciSdkMicronautSerializer without any config options.

There's this TODO:

micronaut-oracle-cloud/oraclecloud-httpclient-netty/src/main/java/io/micronaut/oraclecloud/httpclient/netty/ManagedNettyHttpProvider.java

Line 63 in 651474f

// todo: use serializer from context

Additionally, NettyHttpResponse needs to be adjusted to use the proper mapper.

One option would be to use the JsonMapper from the context. It is already injected in ManagedNettyHttpProvider. This would also restore compatibility with jackson-databind (needs testing though). One potential issue is that global configuration of the mapper would impact the oci sdk, which might not be intended. As of serde 2.0 (time serialization changes), it should work fine with defaults, however.

An alternative would be to use a separate mapper, but allow configuration in the context.