Rule Externalization - Introduce a Rule, RuleProvider and RulesetMetadata API

<ruleset id=”WLS_10_12_TO_EAP_6” phase=”...”>
<metadata>
	<dependencies>
		<addon id=”org.jboss.windup.rules:windup-rules-javaee:2.0.1.Final”>			<addon id=”org.jboss.windup.rules:windup-rules-java:2.0.0.Final”>
		<!-- Do we need a specific version? Perhaps minimal?
                               What if an old rule runs in new windup which needs newer addon? etc.-->
	</dependencies>

	<sourcePlatform id=”weblogic” versionRange=”(10,12]”/>
	<sourceFramework id=”ejb2”/>
	<targetPlatform id=”eap6”/>
	<targetFramework id=”ejb2”/>
	<targetFramework id=”ejb3”/>
	<tags>
		<tag>require-stateless</tag>
		<tag>require-nofilesystem-io</tag>
	</tags>
	<executeAfter></executeAfter>
	<executeBefore></executeBefore>
</metadata>
</ruleset>

    private static void normalizeRuleMetadata(Rule rule)
    {
        if (!(rule instanceof Context))
            return;

        Context ctx = (Context) rule;
        Object category = ctx.get(RuleMetadata.CATEGORY);

        if (category == null)
        {
            ctx.put(RuleMetadata.CATEGORY, new HashSet());
            return;
        }

        if (category instanceof String)
            category = ((String)category).split(WindupRuleProviderBuilder.TAGS_SPLIT_PATTERN);

        if (category instanceof String[])
            category = Arrays.asList((String[]) category);

        if (category instanceof Collection && !(category instanceof Set))
        {
            HashSet categoriesSet = new HashSet();
            for (Object catItem : (Collection) category)
                if (!(catItem instanceof String))
                    throw new WindupException("Rule categories may only contain strings, but contains: " + catItem.getClass().getSimpleName());
                else if ("".equals(catItem))
                    continue;
                else
                    categoriesSet.add(((String)catItem).trim());
            ctx.put(RuleMetadata.CATEGORY, categoriesSet);
        }