Reduce noise for Azure Static Content rule

[agoncal]

This reduces the noise of the Azure Static Content rule. Today it takes all the HTML/CSS/JS files and creates one issue per file. The change is to look only for HTML/HTM files and skip the CSS and JS files.

We could maybe improve this rule to make it less noisy at a later stage (ATM it does not seem possible with the WindUp syntax):

• we could skip the files that are called `index.html and index.html
• we could look for HTML pages only located under src/main/resources
• we could look for HTML pages only located under src/main/webapp

Fix #201

[showpune]

I am just thinking do we still need this rule, especially in java world

In very beginning, the customer developed using jsp and struts, and the html/css is put in CDN.

But for now, as we have rich client and spring mvc, customer will put html/css in java source code, so it is not an issue in java world

[agoncal]

@showpune the rule is described in our migration guide. So let's implement it for now, and maybe later question the migration guide.