Implements Client and server for API1/get-incomplete-t2-A and API1/submit-first-t2-signature/

The client is in src/main/java/io/aie_btc_service/aie_btc_service/tools/SignIncompleteT2.java

The web service is: src/main/java/io/aie_btc_service/aie_btc_service/API1Service.java

You can start the server with: mvn clean package exec:java -Dexec.mainClass=io.aie_btc_service.aie_btc_service.API1Service

You can start the client with: mvn clean package exec:java -Dexec.mainClass=io.aie_btc_service.aie_btc_service.tools.SignIncompleteT2

The client connects to loaclhost.

Missing: "Check if there is open output for giver/taker pubkey, and if there is, return t2-sighash, t2-raw etc. "