Updated code base to make use of these instead of chooseIdentity(). Also improved the serialisation of fiber checkpoints so that it doesn't store the entire cert parth of this identity.
* Remove node's main identitiy from NodeInfo.
Preparation for getting rid of services + supporting multiple identities
on the node.
NodeInfo keeps multiple identities as a list. For now the first one is treated as a special one.
Introduced function chooseIdentity in CoreTestUtils as a preparation for proper handling of multiple identities in the future.
Remove legalIdentityKey from ServiceHub, add extension function - chooseIdentity on ServiceHub.
Add `me` field on FlowStateMachineImplemetation, flows should know what the calling identity is.
Remove SERVICES_PREFIX in artemis messaging layer.
* Address minor comments.
* Fixes after rebase.
Remove chooseIdentity from ServiceHub
* Rename me to ourIdentity on FlowLogic
* Fixes after rebase
* Address Ross comments, fixes
* Fix after rebase
* Fix services certificate paths
Apply Patrick's patch.
* Change to using strings in CordformContext; X500Name is an external API dependency we're trying to avoid, X500Principal rearranges the order of the elements in a way we don't want, and trying to put CordaX500Name into Groovy in the time available is impractical. As such having pre-formatted strings used in the Cordform plugin makes most sense right now.
* Remove uses of CordaX500Name.x500
* Remove old X.500 parsing tools
* Move CordaX500Name.x500 into X500NameUtils
* Move X500NameUtils into internal
* ContractState's contract type has been moved to TransactionState and is now a string representing the class name of the contract class to allow classloading of arbitrary contracts from custom classloaders.
* Upgraded isolated JAR to new version.
