feat: update dockerfile to build only ampd

[eguajardo]

Reduces docker build time by about 4 minutes by only building ampd instead of the whole workspace. Also copies over the whole workspace so there is no need to update every time there is a change in the directory structure.

It seems that the image weights the same (131mb) as the image created before this changes

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.36%. Comparing base (1a8a4cc) to head (5df6a6a).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #759   +/-   ##
=======================================
  Coverage   93.36%   93.36%           
=======================================
  Files         225      225           
  Lines       36359    36359           
=======================================
  Hits        33947    33947           
  Misses       2412     2412           

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[fish-sammy]

I like the idea of building ampd only and excluding unrelated packages and contracts. However, the multi-stage build of ampd itself shouldn't be removed.