support dynamic parameter changes in parameters extension

[atsushieno]

It is similar to #44, but while the issue was about ports it is about parameters this time.

It would be done by adding on_parameter_list_changed(AndroidAudioPluginHost* host, AndroidAudioPlugin* plugin) in parameters host extension, like:

typedef void (*parameters_extension_on_parameter_list_changed_func_t) (AndroidAudioPluginHost* host, AndroidAudioPlugin* plugin);

typedef struct aap_host_parameters_extension_t {
    parameters_extension_on_parameter_list_changed_func_t on_parameters_changed;
    parameters_extension_get_mapping_policy_func_t get_mapping_policy;
};

... assuming that the host can retrieve these properties from AndroidAudioPlugin*:

• pluginId
• instanceId

Especially for instanceId, we currently do not provide it by any way so we will have to add extra changes somewhere (maybe in plugin-info extension).