feat: error if configuration file has unknown properties

[G-Rath]

Currently the scanner does not check if there were unrecognized properties when loading configuration files, meaning that typos can easily slip through; to help avoid this, I've modified tryLoadConfig to return an error if there are any undecoded keys in the metadata.

While this could cause existing configs to start erroring, I don't think this should be considered a breaking change as such configurations would inherently causing different behaviour than what was desired and thus be a downstream bug themselves.

This will also mean that old versions of the scanner going forward would not be compatible with configs for even newer versions of the scanner that introduce new config properties, which is could be a little annoying but I don't think outweighs the benefit of this validation especially given such configurations likewise would result in different behaviour since the old scanner version would not know what to do with the new configuration option.

Resolves #1098

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 67.98%. Comparing base (c3295de) to head (ed9fc4a).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1249      +/-   ##
==========================================
+ Coverage   67.94%   67.98%   +0.03%     
==========================================
  Files         174      174              
  Lines       16839    16847       +8     
==========================================
+ Hits        11442    11454      +12     
+ Misses       4764     4761       -3     
+ Partials      633      632       -1     

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