Move static clients from scheduler to their respective header

[csegarragonz]

No description provided.

[codecov]

Codecov Report

Merging #339 (3630165) into main (74b12aa) will decrease coverage by 0.06%.
The diff coverage is 95.34%.

❗ Current head 3630165 differs from pull request most recent head 613b210. Consider uploading reports for the commit 613b210 to get more accurate results

@@            Coverage Diff             @@
##             main     #339      +/-   ##
==========================================
- Coverage   82.04%   81.98%   -0.06%     
==========================================
  Files          98       98              
  Lines        7964     7972       +8     
==========================================
+ Hits         6534     6536       +2     
- Misses       1430     1436       +6     

Files Changed	Coverage Δ
include/faabric/scheduler/Scheduler.h	42.85% <ø> (ø)
src/planner/PlannerClient.cpp	80.00% <80.00%> (ø)
src/planner/Planner.cpp	92.66% <100.00%> (-0.72%)	⬇️
src/planner/PlannerEndpointHandler.cpp	84.24% <100.00%> (ø)
src/scheduler/FunctionCallClient.cpp	88.42% <100.00%> (+1.21%)	⬆️
src/scheduler/Scheduler.cpp	91.67% <100.00%> (-0.19%)	⬇️
src/snapshot/SnapshotClient.cpp	93.70% <100.00%> (+0.42%)	⬆️

... and 1 file with indirect coverage changes