ExternalProject: retry downloads only on recoverable errors
Add support for the INACTIVITY_TIMEOUT option in the ExternalProject and FetchContent modules. The download retries are performed only when a transcient potentailly recoverable network/access error occurs. In other cases, the download is not retried, leading to a shorter failure response.
Fixes: #20992 (closed)
Topic-rename: ExternalProject-retry-only-recoverable
Edited by Brad King