Inline ContextHandler.MAX_FORM_CONTENT_SIZE_KEY

[basil]

Jetty 10:

jetty-server/src/main/java/org/eclipse/jetty/server/handler/ContextHandler.java
145:    public static final String MAX_FORM_CONTENT_SIZE_KEY = "org.eclipse.jetty.server.Request.maxFormContentSize";

Jetty 12:

jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/FormFields.java
42:    public static final String MAX_LENGTH_ATTRIBUTE = "org.eclipse.jetty.server.Request.maxFormContentSize";

As you can see, the string is the same, but now lives in FormFields.MAX_LENGTH_ATTRIBUTE rather than ContextHandler.MAX_FORM_CONTENT_SIZE_KEY.

To prepare ourselves for the transition, simplest just to inline the string so that we aren't depending on any particular calling convention.

Testing done

mvn clean install