vppinfra: vector allocator rework

vppinfra: vector allocator rework

- support of in-place growth of vectors (if there is available space next to
  existing alloc)
- drops the need for alloc_aligned_at_offset from memory allocator,
  which allows easier swap to different memory allocator and reduces
  malloc overhead
- rework of pool and vec macros to inline functions to improve debuggability
- fix alignment - in many cases macros were not using native alignment
  of the particular datatype. Explicitly setting alignment with XXX_aligned()
  versions of the macro is not needed anymore in > 99% of cases
- fix ASAN usage
- avoid use of vector of voids, this was root cause of several bugs
  found in vec_* and pool_* function where sizeof() was used on voids
  instead of real vector data type
- introduce minimal alignment which is currently 8 bytes, vectors will
  be always aligned at least to that value (underlay allocator actually always
  provide 16-byte aligned allocs)

Type: improvement
Change-Id: I20f4b081bb13bbf7bc0ace85cc4e301787f12fdf
Signed-off-by: Damjan Marion <damarion@cisco.com>