Add a ClientBuilder hook.

[pixlwave]

This PR adds an app hook for modifying the default ClientBuilder . Additionally it adds the necessary setup for app hooks in the NSE (making the hook availability conditional depending on the target).

[github-actions]

	Warnings
⚠️	Some of the commits are missing ticket numbers. Please consider squashing all commits that don't have a tracking number.

Generated by 🚫 Danger Swift against 249d435

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 36 lines in your changes missing coverage. Please review.

Project coverage is 77.76%. Comparing base (95d53f1) to head (249d435).

Files	Patch %	Lines
ElementX/Sources/Application/AppCoordinator.swift	0.00%	7 Missing ⚠️
ElementX/Sources/Hooks/AppHooks.swift	0.00%	7 Missing ⚠️
...X/Sources/Services/QRCode/QRCodeLoginService.swift	0.00%	6 Missing ⚠️
...ervices/Authentication/AuthenticationService.swift	0.00%	4 Missing ⚠️
...ources/Services/UserSession/UserSessionStore.swift	0.00%	4 Missing ⚠️
NSE/Sources/NotificationServiceExtension.swift	0.00%	3 Missing ⚠️
NSE/Sources/Other/NSEUserSession.swift	0.00%	3 Missing ⚠️
...mentX/Sources/Other/Extensions/ClientBuilder.swift	0.00%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #3056      +/-   ##
===========================================
- Coverage    77.76%   77.76%   -0.01%     
===========================================
  Files          695      695              
  Lines        54110    54128      +18     
===========================================
+ Hits         42078    42091      +13     
- Misses       12032    12037       +5     

Flag	Coverage Δ
unittests	68.64% <0.00%> (+0.02%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.