* CORDA-939 Modify Api Scanner to check api for internal exposures (#2510)
* Update check api changes to look for internals
* Update several more uses of internal
* Make check-api-changes script filter out internal class usages
* Make CordaClock part of API
* Update api-current.txt
* Remove exclusion of nodeapi.internal
* Remove access to CordaPersistence from public api
* Don't expose DB Connection from StartedMockNode and remove unnecessary transaction from CustomVaultQueryTest
* Make internal tests that use need db access use InternalMockNetwork
* Make test certificates internal
* Address further review comments
* Revert some accidental changes to api-current.txt
* Address Shams' review comments
* Update Api Scanner to filter out CordaInternal attribute
* Update api-current.txt
* Remove superfluous brackets
* Add transaction to StartedMockNode
* More leaky transaction fixes
# Conflicts:
# .ci/api-current.txt
# node-api/src/test/kotlin/net/corda/nodeapi/internal/AttachmentsClassLoaderStaticContractTests.kt
# node-api/src/test/kotlin/net/corda/nodeapi/internal/AttachmentsClassLoaderTests.kt
# node/src/integration-test/kotlin/net/corda/node/services/AttachmentLoadingTests.kt
# node/src/test/kotlin/net/corda/node/internal/cordapp/CordappProviderImplTests.kt
# testing/node-driver/src/main/kotlin/net/corda/testing/node/internal/InternalMockNetwork.kt
# testing/test-utils/src/main/kotlin/net/corda/testing/internal/MockCordappConfigProvider.kt
# testing/test-utils/src/main/kotlin/net/corda/testing/internal/MockCordappProvider.kt
* Bump gradle plugins version
* One last internal exposure
* Update constants.properties
* Fix api-current
* Address mikes review comments
* Skeleton plugin.
* Implement Gradle api-scanner plugin, and apply it.
* Generate API documentation for any jar without a classifier.
* Fix usage of smokeTests classifier.
* Tweak Gradle API usage.
* Upgrade to fast-classpath-scanner 2.7.0
* Include interfaces and more modifiers in the class description.
* Allow system classes to be supertypes and implemented interfaces.
* Make API Scanner plugin configuration tweakable via build.gradle.
* Add a miserable amount of unit testing.
* Sort methods and fields using their natural comparators. Way easier!
* Add README for api-scanner plugin.
* Add @OutputFiles to ScanApiTask.
* Rename ScanApiTask to ScanApi.
* Allow the ScanApi task to be disabled.
* WIP: Create a top-level GenerateApi task to collate the ScanApi output.
* Exclude package-private classes, as well as bridge/synthetic methods.
* Replace "End of Class" delimiter with '##'.
* Don't scan modules whose API is still "in flux".
* Include constructors in the API definitions.
* Finish implementation of GenerateApi task.
* Update README to include GenerateApi task.
* Filter out Kotlin's "internal" methods.
* Assign "fatjar" classifier to the fat jar artifact.
* Enhance README for GenerateApi.
* Explain effect of api-scanner plugin, and link to Corda's API strategy.
* Tweak README
* Exclude synthetic Kotlin classes by analysing @Metadata.
* Allow us to exclude some classes explicitly from the API.
