Merge stable 1.7 into stable 1.8

Merge stable-1.6 into stable-1.7

docker: make build- and push-image scripts more verbose

Merge stable-1.5 into stable-1.6

otherwise it will still use found (most likely, newer) clang-format.

Update doxygen settings

concurrent_hash_map: make double to size_t cast explicit in defragment()

bump docker images versions

and set clang-format to fixed version (6.0).

and make sure only indexes up to max_index are used.

fixes #854

get rid of old WA for vcpkg and use latest release instead

add missing comment's char in archlinux docker image

Cleanup CI files

based on PMDK's commit 96db274c7, added:
- '-j' param to coverity command (make)
- necessary vars for coverity script (used for Travis CI)
- Coverity certificate download
- skip for forked repos

and do minor cleanup in docker scripts.

- add skip arguments/flags for PMDK and Valgrind builds
- move env variable settings to the top of the files

concurrent_hash_map: fix free_data()

Setting ptr to null after calling delete_persistent is required to
ensure proper recovery.

If free_data() was called twice this led to assertion failure and
possible double free.

This patch skips freeing data when tls_ptr is already nullptr.

Apply vcpkg patch for pmdk (stable 1.9)

It's a workaround, until vcpkg issue is fixed:
https://github.com/microsoft/vcpkg/issues/11096

Merge stable-1.8 into stable-1.9