* ENT-1670: update kdocs and unit test for better user experience regarding
RPC connection loss
* RPCStabilityTests: move doOnError logic to onError handler
Prior to this change it was intermittently failing with:
```
net.corda.client.rpc.RPCException: RPC server is not available.
at net.corda.client.rpc.internal.RPCClientProxyHandler.invoke(RPCClientProxyHandler.kt:222)
at com.sun.proxy.$Proxy79.ping(Unknown Source)
at net.corda.client.rpc.RPCStabilityTests$client reconnects to rebooted server$1$pingFuture$1.invoke(RPCStabilityTests.kt:251)
at net.corda.client.rpc.RPCStabilityTests$client reconnects to rebooted server$1$pingFuture$1.invoke(RPCStabilityTests.kt:36)
at net.corda.core.internal.concurrent.ValueOrException$DefaultImpls.capture(CordaFutureImpl.kt:107)
at net.corda.core.internal.concurrent.OpenFuture$DefaultImpls.capture(CordaFutureImpl.kt:65535)
at net.corda.core.internal.concurrent.CordaFutureImpl.capture(CordaFutureImpl.kt:119)
at net.corda.core.internal.concurrent.CordaFutureImplKt$fork$$inlined$also$lambda$1.run(CordaFutureImpl.kt:22)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:748)
```
* Improve error reporting in case of failure of flaky tests
Also eliminate warnings and other minor changes.
* Address code review comments raised by @exFalso
Also improve output for stack traces.
* rework message handling while connection is down: do not send anything, throw on all obs and futures when failure detected
* RPC calls will throw if used during failover; adapted tests
ENT-1575 Add db migrations for db attachment changes,
ENT-1566 Fixes for db integration tests -following changes in CORDA-926 (obligatory node properties), upgrade db schema setup in draining mode/RPC tests, set runMigration=true in properties files for db tests, add new tables for deletion in SQL setup scrips
Updated db integration tests description in testing.rst
* CORDA-296: added handler for connection failover
print rpc address during node startup
* address PR comments: typo, whitespace, onError observables
* reworked rpc client msg buffering to avoid race conditions when failure happens while the request is being prepared to be sent; added unit test for 8 threads sharing same client sending 1000 requests
* decreased sleep time in rpc test, code cleanup
- Existing embedded Shell connects via RPC including checking RPC user credentials (before was a direct use of CordaRPCOps): in dev mode when console terminal is enabled, node created `shell` user.
- New Standalone Shell app with the same functionalities as Shell: connects to a node via RPC Client, can use SSL and run SSH server.
* CORDA-986 and CORDA-985 CompositeKey and Signature verification performance fixes (#2467)
* CORDA-696: Create separate transaction types for contract upgrade transactions.
Add rationale around upgrade transactions
Move contract upgrade transaction resolution logic into internal until it's stabilised.
Throw a better exception when contract attachment not found
Default legacy contract constraint to always accepting - needs to be changed to whitelist constraint before merging
Introduce a new upgraded contract interface that allows specifying the legacy constraint.
Remove StateLoader, make all tx resolution functions take in ServicesForResolution
Contract upgrade transactions can handle whitelist by zone constraints
When creating a contract upgrade transaction, make sure the attachment of the old cordapp gets attached when using hash constraints.
Attachment lookup for a given contract class name only scans currently loaded cordapps, and we don't load old versions of cordapps.
CORDA-696: Update upgrade docs
Also for "client/rpc" explicitly specify "jvmTarget" (similar to what "experimental/behave" does) to avoid ambiguity.
Without this change the following compilation error been observed in IntelliJ:
Z:\corda\experimental\behave\src\main\kotlin\net\corda\behave\node\Node.kt
Error:(163, 44) Kotlin: Cannot inline bytecode built with JVM target 1.8 into bytecode that is being built with JVM target 1.6. Please specify proper '-jvm-target' option
* Remove sslConfiguration from public constructor of CordaRPCClient
* Address review comments
* Update api-current.txt
* sslConfiguration doesn't need to be a property
