(WIP) Add SyncService client from EGW

[tatu-at-datastax]

What this PR does:

Embeds sync-service validation call code from EGW into Data API, to prepare for removal of EGW

Which issue(s) this PR fixes:
Part of #2387

Checklist

• Changes manually tested
• Automated Tests added/updated
• Documentation added/updated
• CLA Signed: DataStax CLA

[github-actions]

📉 Unit Test Coverage Delta vs Main Branch

Metric	Value
Main Branch	50.07%
This PR	49.80%
Delta	🔴 -0.27%
⚠️ Coverage decreased

[github-actions]

Unit Test Coverage Report

Overall Project	49.8% -0.55%	🍏
Files changed	1.75%	❌

File	Coverage
DataVectorizer.java	50.99%	🍏
EmbeddingProviderFactory.java	19.75% -6.17%	❌
SyncServiceClient.java	2.73% -97.27%	❌
VectorizeConfigValidator.java	0% -1.7%	❌
SyncServiceCredentialResolvingProvider.java	0%	❌
SyncServiceErrorMessageMapper.java	0%	❌

[github-actions]

📉 Integration Test Coverage Delta vs Main Branch (dse69-it)

Metric	Value
Main Branch	70.41%
This PR	70.19%
Delta	🔴 -0.21%
⚠️ Coverage decreased

[github-actions]

Integration Test Coverage Report (dse69-it)

Overall Project	70.19% -0.33%	🍏
Files changed	16.25%	❌

File	Coverage
VectorizeConfigValidator.java	88.86%	🍏
EmbeddingProviderFactory.java	57.47%	🍏
DataVectorizer.java	39.95%	🍏
SyncServiceClient.java	18.75% -81.25%	❌
SyncServiceErrorMessageMapper.java	0%	❌

[github-actions]

📉 Integration Test Coverage Delta vs Main Branch (hcd-it)

Metric	Value
Main Branch	72.15%
This PR	71.93%
Delta	🔴 -0.22%
⚠️ Coverage decreased

[github-actions]

Integration Test Coverage Report (hcd-it)

Overall Project	71.93% -0.33%	🍏
Files changed	16.25%	❌

File	Coverage
VectorizeConfigValidator.java	88.86%	🍏
EmbeddingProviderFactory.java	57.47%	🍏
DataVectorizer.java	39.95%	🍏
SyncServiceClient.java	18.75% -81.25%	❌
SyncServiceErrorMessageMapper.java	0%	❌