Add log for order created uid

[sunce86]

This PR adds logging of the newly created order's Uid.

Using this Uid and the log timestamp we can connect the orderbook::api::request_summary log with the order logs in the solver.

Tried to find the cleaner way to add this log directly to the orderbook, but once the response is wrapped into ApiReply it becomes cumbersome to extract the needed Uid.

[codecov-commenter]

Codecov Report

Merging #199 (307ef90) into main (c346f3a) will decrease coverage by 0.26%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##             main     #199      +/-   ##
==========================================
- Coverage   64.71%   64.44%   -0.27%     
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  Files         190      189       -1     
  Lines       39045    38751     -294     
==========================================
- Hits        25268    24974     -294     
  Misses      13777    13777