Add oauth2 Client Credentials Flow

[knoppiks]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 98.33333% with 1 line in your changes missing coverage. Please review.

Project coverage is 96.24%. Comparing base (7fd18b1) to head (87073ec).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
...care/smith/fts/util/auth/HttpServerOAuth2Auth.java	90.90%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main     #457      +/-   ##
============================================
+ Coverage     96.18%   96.24%   +0.06%     
  Complexity      415      415              
============================================
  Files           108      111       +3     
  Lines          1545     1599      +54     
  Branches         42       43       +1     
============================================
+ Hits           1486     1539      +53     
- Misses           42       43       +1     
  Partials         17       17              

Files with missing lines	Coverage Δ
...fts/tca/consent/FhirConsentedPatientsProvider.java	100.00% <100.00%> (ø)
...a/consent/configuration/GicsFhirConfiguration.java	100.00% <ø> (ø)
...uration/GpasFhirDeIdentificationConfiguration.java	100.00% <ø> (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	100.00% <100.00%> (ø)
.../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)
... and 2 more