AppDirectory+Shell integration

[BalassaMarton]

Adds the AppDirectory to the Shell
Refactored configuration of FDC3-related services

[codecov]

Codecov Report

Merging #360 (7fd5d5f) into main (3efe2e8) will decrease coverage by 0.12%.
Report is 1 commits behind head on main.
The diff coverage is 10.52%.

@@            Coverage Diff             @@
##             main     #360      +/-   ##
==========================================
- Coverage   77.53%   77.41%   -0.12%     
==========================================
  Files         160      161       +1     
  Lines        5431     5438       +7     
  Branches      233      233              
==========================================
- Hits         4211     4210       -1     
- Misses       1219     1227       +8     
  Partials        1        1              

Files Changed	Coverage Δ
...DependencyInjection/ServiceCollectionExtensions.cs	100.00% <ø> (+50.00%)	⬆️
src/shell/dotnet/Shell/App.xaml.cs	0.00% <0.00%> (ø)
src/shell/dotnet/Shell/Fdc3/Fdc3Options.cs	0.00% <0.00%> (ø)
...pDirectory/src/AppDirectory/AppDirectoryOptions.cs	100.00% <100.00%> (ø)
...ent/DependencyInjection/Fdc3DesktopAgentBuilder.cs	100.00% <100.00%> (+22.22%)	⬆️
...ent/DependencyInjection/Fdc3DesktopAgentOptions.cs	100.00% <100.00%> (ø)
.../DesktopAgent/src/DesktopAgent/Fdc3DesktopAgent.cs	93.75% <100.00%> (ø)