Feature/t13547 tag enhancements

[niden]

Hello!

• Type: new feature
• Link to issue: Introduce Tag::renderTitle() and change Tag::getTitle() #13547

In raising this pull request, I confirm the following (please check boxes):

• I have read and understood the Contributing Guidelines?
• I have checked that another pull request for this purpose does not exist.
• I wrote some tests for this PR.

Changed Phalcon\Tag::getTitle(). It returns only the text set with setTitle(). If there has been prepend and append text it will be returned by default. It accepts prepend, append booleans to prepend or append the relevant text to the title.

Added Phalcon\Tag::renderTitle() that renders the title enclosed in <title> tags.

Thanks

[niden]

cc @sergeyklay