Chore(dependabot): Add nuget projects

[kruplm]

Since dependabot doesn't support glob syntax it can't pick up the nuget dependencies in a multi-project repository easily.
This pull request adds the main projects under the src folder, and one prototype as a test.
Folders are specified for the project files.
I intend to add other projects later.
Tested on my fork

[codecov]

Codecov Report

Merging #254 (53eae7f) into main (b9b7611) will increase coverage by 0.03%.
The diff coverage is n/a.

❗ Current head 53eae7f differs from pull request most recent head 6555648. Consider uploading reports for the commit 6555648 to get more accurate results

@@            Coverage Diff             @@
##             main     #254      +/-   ##
==========================================
+ Coverage   74.72%   74.75%   +0.03%     
==========================================
  Files         155      155              
  Lines        5475     5475              
  Branches      233      233              
==========================================
+ Hits         4091     4093       +2     
+ Misses       1383     1381       -2     
  Partials        1        1              

see 1 file with indirect coverage changes