Merge branch 'en/strmap' into en/merge-ort-impl

* en/strmap: shortlog: use strset from strmap.h Use new HASHMAP_INIT macro to simplify hashmap initialization strmap: take advantage of FLEXPTR_ALLOC_STR when relevant strmap: enable allocations to come from a mem_pool strmap: add a strset sub-type strmap: split create_entry() out of strmap_put() strmap: add functions facilitating use as a string->int map strmap: enable faster clearing and reusing of strmaps strmap: add more utility functions strmap: new utility functions hashmap: provide deallocation function names hashmap: introduce a new hashmap_partial_clear() hashmap: allow re-use after hashmap_free() hashmap: adjust spacing to fix argument alignment hashmap: add usage documentation explaining hashmap_free[_entries]()