Reverb reconfiguration in runtime

Bug description

IVAS decoder and renderer implement API functions for feeding the library with a renderer configuration data, including acoustic environment data. These functions are:

IVAS_DEC_FeedRenderConfig(hIvasDec, renderConfig);

and

IVAS_REND_FeedRenderConfig(hIvasRend, renderConfig);

This update enables calling these function after initialization to update reverb characteristics.

Description of the change

Initially, the underlying reverb initialization functions were split into open and init functions respectively. Hence, the init functions can be called multiple times eventually. Following the review remarks, the split was reverted and the changes were integrated within the open function. The open function handles initialization and reinitialization differently, based on whether a reverb handle already exists.

Related to #1053 (closed)