WIP: #496: Update JDK version to 11. Remove okhttp dependency and replace …

[cavazosjoe]

…usages with JDK 11 HttpClient. Import Apache CXF for server-side-event (SSE) handling.

[codecov]

Codecov Report

Attention: Patch coverage is 73.79808% with 109 lines in your changes missing coverage. Please review.

Project coverage is 81.45%. Comparing base (6104e7c) to head (012971e).

Files with missing lines	Patch %	Lines
.../main/java/org/stellar/sdk/requests/SSEStream.java	0.00%	19 Missing ⚠️
...ain/java/org/stellar/sdk/http/Jdk11HttpClient.java	76.47%	9 Missing and 7 partials ⚠️
...g/stellar/sdk/requests/AccountsRequestBuilder.java	28.57%	1 Missing and 9 partials ⚠️
src/main/java/org/stellar/sdk/Server.java	84.21%	8 Missing and 1 partial ⚠️
src/main/java/org/stellar/sdk/UriBuilder.java	88.60%	4 Missing and 5 partials ⚠️
...in/java/org/stellar/sdk/http/sse/CxfSseClient.java	0.00%	9 Missing ⚠️
...java/org/stellar/sdk/requests/ResponseHandler.java	77.41%	4 Missing and 3 partials ⚠️
...va/org/stellar/sdk/http/sse/CxfSseEventStream.java	84.21%	5 Missing and 1 partial ⚠️
src/main/java/org/stellar/sdk/UriUtil.java	25.00%	3 Missing ⚠️
src/main/java/org/stellar/sdk/SorobanServer.java	81.81%	2 Missing ⚠️
... and 15 more

Additional details and impacted files

@@             Coverage Diff              @@
##             master     #674      +/-   ##
============================================
+ Coverage     81.03%   81.45%   +0.42%     
- Complexity     1175     1245      +70     
============================================
  Files           200      209       +9     
  Lines          4444     4621     +177     
  Branches        374      381       +7     
============================================
+ Hits           3601     3764     +163     
+ Misses          612      611       -1     
- Partials        231      246      +15     

Files with missing lines	Coverage Δ
src/main/java/org/stellar/sdk/http/GetRequest.java	100.00% <100.00%> (ø)
...rc/main/java/org/stellar/sdk/http/HttpRequest.java	100.00% <100.00%> (ø)
...org/stellar/sdk/requests/AssetsRequestBuilder.java	80.00% <100.00%> (ø)
.../sdk/requests/ClaimableBalancesRequestBuilder.java	72.72% <100.00%> (ø)
...g/stellar/sdk/requests/FeeStatsRequestBuilder.java	50.00% <100.00%> (ø)
...lar/sdk/requests/LiquidityPoolsRequestBuilder.java	57.14% <100.00%> (ø)
.../java/org/stellar/sdk/requests/RequestBuilder.java	78.46% <100.00%> (+0.33%)	⬆️
...sdk/requests/StrictReceivePathsRequestBuilder.java	83.33% <100.00%> (ø)
.../sdk/requests/TradeAggregationsRequestBuilder.java	62.50% <100.00%> (ø)
...rc/main/java/org/stellar/sdk/http/PostRequest.java	90.90% <90.90%> (ø)
... and 24 more