Add oauth2 Client Credentials Flow

[knoppiks]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 97.22222% with 2 lines in your changes missing coverage. Please review.

Project coverage is 96.15%. Comparing base (77b8166) to head (35d3194).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
...care/smith/fts/util/auth/HttpServerOAuth2Auth.java	91.30%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main     #457      +/-   ##
============================================
- Coverage     96.18%   96.15%   -0.03%     
  Complexity      415      415              
============================================
  Files           108      111       +3     
  Lines          1545     1611      +66     
  Branches         42       43       +1     
============================================
+ Hits           1486     1549      +63     
- Misses           42       44       +2     
- Partials         17       18       +1     

Files with missing lines	Coverage Δ
...fts/tca/consent/FhirConsentedPatientsProvider.java	100.00% <100.00%> (ø)
...n/java/care/smith/fts/util/AgentConfiguration.java	100.00% <100.00%> (ø)
...ain/java/care/smith/fts/util/HttpClientConfig.java	100.00% <100.00%> (ø)
...ain/java/care/smith/fts/util/WebClientFactory.java	97.05% <100.00%> (-2.95%)	⬇️
.../java/care/smith/fts/util/auth/HttpClientAuth.java	100.00% <100.00%> (ø)
...care/smith/fts/util/auth/HttpClientOAuth2Auth.java	100.00% <100.00%> (ø)
...care/smith/fts/util/auth/HttpServerAuthConfig.java	100.00% <100.00%> (ø)
...care/smith/fts/util/auth/HttpServerAuthMethod.java	100.00% <100.00%> (ø)
.../util/auth/OAuth2ConfigurationExistsCondition.java	100.00% <100.00%> (ø)
...care/smith/fts/util/auth/HttpServerOAuth2Auth.java	91.30% <91.30%> (ø)