refactor: optimize mem usage and cleanup dependencies

[mmta]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 94.65649% with 7 lines in your changes are missing coverage. Please review.

Project coverage is 93.90%. Comparing base (f76b334) to head (7c09045).
Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #35      +/-   ##
==========================================
- Coverage   93.93%   93.90%   -0.04%     
==========================================
  Files          27       27              
  Lines        5524     5529       +5     
==========================================
+ Hits         5189     5192       +3     
- Misses        335      337       +2     

Flag	Coverage Δ
unittests	93.90% <94.65%> (-0.04%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
server/src/asset.rs	99.31% <100.00%> (+<0.01%)	⬆️
server/src/backlog.rs	97.17% <100.00%> (-0.05%)	⬇️
server/src/directive.rs	99.01% <100.00%> (+<0.01%)	⬆️
server/src/intel.rs	97.05% <100.00%> (+0.18%)	⬆️
server/src/manager.rs	92.57% <100.00%> (+0.19%)	⬆️
server/src/rule.rs	100.00% <100.00%> (ø)
server/src/vuln.rs	97.19% <100.00%> (+0.13%)	⬆️
server/src/watchdog.rs	90.51% <ø> (ø)
server/src/worker.rs	90.64% <0.00%> (ø)
server/src/bin/dsiem-frontend.rs	83.48% <0.00%> (+0.38%)	⬆️
... and 1 more