Reverts the following commits:
- c81ec6f26d40b70283958a4ef3e216fb32cbaf14:
"Exposes capture methods to AudioServer, variable renames for
consistency, added documentation."
- 47c558b98abf842910c780294314326662410cdf:
"Expose audio callbacks as signals."
- dabaa11b3c451e9b8f2cca7e563bd9ec51edb169:
"Fix to make sure the capture buffers are deallocated at shutdown.
Silences warnings."
Some documentation improvements were kept for pre-existing methods.
See rationale for reverting these changes in #30468.
837adb30fd