Public API for UI Hook exporting

Created by: stefanoborini

Added base extension plugin entry for UI hooks and entries to the API.

This PR is a follow up of #93 (public side)

Created by: codecov[bot]

Codecov Report

Merging #94 into master will increase coverage by 0.01%. The diff coverage is 100%.

@@            Coverage Diff             @@
##           master      #94      +/-   ##
==========================================
+ Coverage   97.45%   97.47%   +0.01%     
==========================================
  Files          63       63              
  Lines         944      949       +5     
  Branches       68       68              
==========================================
+ Hits          920      925       +5     
  Misses         21       21              
  Partials        3        3

Impacted Files	Coverage Δ
force_bdss/api.py	100% <100%> (ø)
force_bdss/base_extension_plugin.py	100% <100%> (ø)

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