Added custom allocators to the memory submodule

[akukh]

Closes: #17

[codecov]

Codecov Report

Attention: Patch coverage is 93.54839% with 46 lines in your changes are missing coverage. Please review.

Project coverage is 94.68%. Comparing base (8eaba95) to head (449f8bb).

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #20      +/-   ##
==========================================
- Coverage   97.96%   94.68%   -3.28%     
==========================================
  Files           5       14       +9     
  Lines         245      958     +713     
  Branches       12       84      +72     
==========================================
+ Hits          240      907     +667     
- Misses          0        2       +2     
- Partials        5       49      +44     

Files	Coverage Δ
flux-foundation/flux/foundation/memory/align.hpp	94.74% <94.74%> (ø)
...foundation/flux/foundation/memory/memory_block.hpp	80.00% <80.00%> (ø)
...n/flux/foundation/memory/std_allocator_adapter.hpp	94.60% <94.60%> (ø)
...ation/flux/foundation/memory/allocator_storage.hpp	98.20% <98.20%> (ø)
...dation/flux/foundation/memory/static_allocator.hpp	89.19% <89.19%> (ø)
...-foundation/flux/foundation/memory/memory_pool.hpp	91.67% <91.67%> (ø)
...foundation/flux/foundation/memory/memory_stack.hpp	92.00% <92.00%> (ø)
...dation/flux/foundation/memory/memory_pool_list.hpp	92.18% <92.18%> (ø)
...foundation/flux/foundation/memory/memory_arena.hpp	92.90% <92.90%> (ø)