LPS-48615 Send email for blog updates when the user manually does it

Hey Brian,

This is in reply to: https://github.com/brianchandotcom/liferay-portal/pull/21257#issuecomment-56992170

I named the variable `emailEntryUpdatedComment` and `sendEmailEntryUpdated` to be consistent with the variable defined in blogs_admin/configuration.jsp: `emailEntryUpdatedBody` and `blogsSettings.isEmailEntryUpdatedEnabled()`but we can change it to a better name if you have any idea. 

Regarding the method name givenThatBlogSendsEmailEntryUpdatedBasedOnUserComments I meant that the BlogService is configured to send email when updating a blog entry and include the comments of the blogger about why he updated the blog entry.

Hope it makes sense.

Let me know if you have any other question.

Thanks Brian,