gperftools: add new package

gperftools: add new package

Thread-caching malloc provided by this package improves snort3
performance.  I have been running with this for over seven months
without issues.  Avg CPU usage is down.  Another user reported
higher throughput achieved with snort3 compiled with this on
samba transfers on system with CPU-limited snort performance.[1]

1. https://forum.openwrt.org/t/some-help-with-a-makefile-gperftools/165656/22

Build system: x86/64
Build-tested: x86/64
Run-tested: x86/64

Signed-off-by: John Audia <[email protected]>