Migrate to use built-in RPC client

[Shaptic]

We should use the RPC SDK when possible instead of building requests by hand

This does somewhat depend on #141 for general sanity.

[sreuland]

lgtm. If you wanted to test the test, locally:

make \
    CORE_GIT_REF=https://github.com/stellar/stellar-core.git#v23.0.0rc4 \
    STELLAR_RPC_GIT_REF=https://github.com/stellar/stellar-rpc.git#vv23.0.0-rc.2 \
    SOROBAN_CLI_GIT_REF=https://github.com/stellar/stellar-cli.git#v23.0.0 \
    RS_XDR_GIT_REF=v23.0.0-rc.2 \
    GO_GIT_REF=https://github.com/stellar/go.git#v23.0.0-rc2
    JS_STELLAR_SDK_NPM_VERSION=v14.0.0-rc.3 \
    build

docker run --rm -t --name e2e_test \
stellar/system-test:dev \
--VerboseOutput true \
--SorobanExamplesGitHash v22.0.1

I get most of the versions from the qs build-testing target

[Shaptic]

@sreuland building core takes forever heh but I'm running it right now, will merge once it passes

[sreuland]

@sreuland building core takes forever heh but I'm running it right now, will merge once it passes

doh, yes, you can bypass the core build-from-source time by referring to a pre-built core image with SYSTEM_TEST_CORE_IMAGE and SYSTEM_TEST_CORE_IMAGE_BIN_PATH, rpc uses this shortcut on it's e2e.yml for reference.

[sreuland]

@fnando , just a heads up on these changes which will be landing on master, they should be transparent to running tests, the stellar-clil e2e ci step builds and runs system-test go module directly using system-test/test.yml