Add sortmode for Trie + bugfix score sorting

[ashtul]

Add two sorting modes: by lexigraphic order and by score order.
Sorting mode is set when Trie is initialized.
Sorting node children now takes place on writes only (add/delete). Before this change, nodes were sorted during queries, making the data structure unsafe for multi-readers.

typedef enum {
  Trie_Sort_Lex = 0,
  Trie_Sort_Score = 1,
} TrieSortMode;

Bug Fix - The default sort by score had a bug exposed in the test_cpp_trie.

replaces #2951

[MeirShpilraien]

👍 Look good, one comment.

[codecov]

Codecov Report

Merging #2952 (d004545) into master (63d1dff) will increase coverage by 0.00%.
The diff coverage is 93.02%.

❗ Current head d004545 differs from pull request most recent head 2d73f27. Consider uploading reports for the commit 2d73f27 to get more accurate results

@@           Coverage Diff           @@
##           master    #2952   +/-   ##
=======================================
  Coverage   81.94%   81.94%           
=======================================
  Files         180      180           
  Lines       29429    29430    +1     
=======================================
+ Hits        24115    24116    +1     
  Misses       5314     5314           

Impacted Files	Coverage Δ
src/spec.c	86.01% <60.00%> (ø)
src/trie/trie.c	94.79% <96.66%> (ø)
src/dictionary.c	90.40% <100.00%> (ø)
src/redisearch_api.c	89.49% <100.00%> (ø)
src/spell_check.c	98.28% <100.00%> (ø)
src/suggest.c	90.98% <100.00%> (ø)
src/trie/trie_type.c	83.09% <100.00%> (+0.07%)	⬆️

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