[INFRA] Move checkstyle config files to one location (#3056)

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#### Which Delta project/connector is this regarding?
<!--
Please add the component selected below to the beginning of the pull
request title
For example: [Spark] Title of my pull request
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- [ ] Spark
- [ ] Standalone
- [ ] Flink
- [ ] Kernel
- [X] Other (INFRA)

## Description

Currently the java checkstyle config files are shared by some projects
and stored in different locations nested under those projects. Moves the
checkstyle config files to a common location. This will make it easier
to compare our configs in the future and keep track of the different
settings for the different projects.

## How was this patch tested?

Locally ran `checkstyle` for all the affected projects. Also modified
one file and checked that the checks failed.

Author: allisonport-db

build.sbt

@@ -368,7 +368,7 @@ lazy val kernelApi = (project in file("kernel/kernel-api"))
            |""".stripMargin)
       Seq(file)
     },
-    javaCheckstyleSettings("kernel/dev/checkstyle.xml"),
+    javaCheckstyleSettings("dev/kernel-checkstyle.xml"),
     // Unidoc settings
     unidocSourceFilePatterns := Seq(SourceFilePattern("io/delta/kernel/")),
   ).configureUnidoc(docTitle = "Delta Kernel")
@@ -406,7 +406,7 @@ lazy val kernelDefaults = (project in file("kernel/kernel-defaults"))
       "org.apache.spark" %% "spark-core" % defaultSparkVersion % "test" classifier "tests",
       "org.apache.spark" %% "spark-catalyst" % defaultSparkVersion % "test" classifier "tests",
     ),
-    javaCheckstyleSettings("kernel/dev/checkstyle.xml"),
+    javaCheckstyleSettings("dev/kernel-checkstyle.xml"),
       // Unidoc settings
     unidocSourceFilePatterns += SourceFilePattern("io/delta/kernel/"),
   ).configureUnidoc(docTitle = "Delta Kernel Defaults")
@@ -1066,7 +1066,7 @@ lazy val standalone = (project in file("connectors/standalone"))
 
     // Unidoc setting
     unidocSourceFilePatterns += SourceFilePattern("io/delta/standalone/"),
-    javaCheckstyleSettings("connectors/dev/checkstyle.xml")
+    javaCheckstyleSettings("dev/connectors-checkstyle.xml")
   ).configureUnidoc()
 
 
@@ -1251,7 +1251,7 @@ lazy val flink = (project in file("connectors/flink"))
     unidocSourceFilePatterns += SourceFilePattern("io/delta/flink/"),
     // TODO: this is the config that was used before archiving connectors but it has
     //  standalone-specific import orders
-    javaCheckstyleSettings("connectors/dev/checkstyle.xml")
+    javaCheckstyleSettings("dev/connectors-checkstyle.xml")
   ).configureUnidoc()
 
 /**

connectors/dev/checkstyle-suppressions.xml

@@ -72,7 +72,7 @@
     <module name="NewlineAtEndOfFile"/>
 
     <module name="RegexpHeader">
-        <property name="headerFile" value="kernel/dev/copyrightHeader"/>
+        <property name="headerFile" value="dev/copyrightHeader"/>
     </module>
 
     <module name="TreeWalker">