Return the plugin-apis to this repo (#1900)

* Return plugin-api to the main repo
* Spotless
* Migrate all external plugin-api references to the project in this repo
* Add licence header
* Update repo reference for publish, even if commented
* Use real configuration for publishing plugin-api

This was tested with the
`:plugins:publishMavenJavaPublicationToMavenLocal` task and checking the
local Maven repo to make sure it was using the correct paths

Signed-off-by: Edward Evans <edward.evans@consensys.net>

Signed-off-by: Adrian Sutton <adrian.sutton@consensys.net>

services/kvstore/build.gradle

@@ -26,10 +26,9 @@ jar {
 }
 
 dependencies {
+  api project(':plugins')
   api project(':util')
 
-  api 'tech.pegasys.pantheon:plugin-api'
-
   implementation project(':metrics:core')
   implementation project(':metrics:rocksdb')
   implementation project(':services:util')

services/pipeline/build.gradle

@@ -28,10 +28,10 @@ jar {
 dependencies {
   api project(':util')
   implementation project(':metrics:core')
+  implementation project(':plugins')
 
   implementation 'org.apache.logging.log4j:log4j-api'
   implementation 'com.google.guava:guava'
-  implementation 'tech.pegasys.pantheon:plugin-api'
 
   runtime 'org.apache.logging.log4j:log4j-core'
 

services/tasks/build.gradle

@@ -26,10 +26,9 @@ jar {
 }
 
 dependencies {
+  api project(':plugins')
   api project(':util')
 
-  api 'tech.pegasys.pantheon:plugin-api'
-
   compileOnly 'org.openjdk.jmh:jmh-generator-annprocess'
 
   implementation project(':metrics:core')