Build: Getting Rid of `folly`

When migrating to ubuntu22 I cannot get folly to compile / build:

• On the tag we use v2019.11.11.00
• On the latest master

$ grep -ir folly src/
src/smf_app/smf_pfcp_association.hpp:#include <folly/AtomicHashMap.h>
src/smf_app/smf_pfcp_association.hpp:#include <folly/AtomicLinkedList.h>
src/smf_app/smf_pfcp_association.hpp:  folly::AtomicHashMap<int32_t, std::shared_ptr<pfcp_association>> associations;
src/smf_app/smf_pfcp_association.cpp:  folly::AtomicHashMap<int32_t, std::shared_ptr<pfcp_association>>::iterator it;
src/smf_app/smf_pfcp_association.cpp:  folly::AtomicHashMap<int32_t, std::shared_ptr<pfcp_association>>::iterator it;
src/smf_app/smf_pfcp_association.cpp:  folly::AtomicHashMap<int32_t, std::shared_ptr<pfcp_association>>::iterator it;
src/smf_app/smf_pfcp_association.cpp:  folly::AtomicHashMap<int32_t, std::shared_ptr<pfcp_association>>::iterator it;

It is not used for much. An alternative (boost) would be nice.