Trim space around CDATA elements before extracting the CharData.
This problem was discovered when reading https://www.sethvargo.com/feed.xml.
Title and Summary fields have newlines and space between the <title>
element and the CDATA element. e.g.
<title>
<![CDATA[Entry title here]]>
</title>
This meant the title of the feed was coming into MiniFlux as,
<![CDATA[Entry title here]]>
Some technical blogs have titles like "</some-title>" or "This is some <code>source code</code>".
Miniflux was removing these elements which prevent rendering the title correctly.
