Refactor initialize

[GDYendell]

• Depends on API Fixes #29

Separate initialize into logical steps:

• Send requests to detector
• Handle key clashes
• Create attributes

This removes the limitation that key clashes are only handled between adjacent subsystems.

[codecov]

Codecov Report

Attention: Patch coverage is 32.05128% with 53 lines in your changes are missing coverage. Please review.

Project coverage is 43.29%. Comparing base (bb8e27e) to head (4bf7cba).
Report is 7 commits behind head on main.

❗ Current head 4bf7cba differs from pull request most recent head 9affc2b. Consider uploading reports for the commit 9affc2b to get more accurate results

Files	Patch %	Lines
src/eiger_fastcs/eiger_controller.py	34.84%	43 Missing ⚠️
src/eiger_fastcs/http_connection.py	16.66%	10 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #30      +/-   ##
==========================================
+ Coverage   39.03%   43.29%   +4.25%     
==========================================
  Files           4        4              
  Lines         228      261      +33     
==========================================
+ Hits           89      113      +24     
- Misses        139      148       +9     

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