[Feature Enhancement][jenkins-rss-to-trello-md.py] timestamp filter

[Taihsiang Ho]

Automatically striking-through jobs that are passed in the past 7 days (or during the weekend), or highlighting jobs that have not passed, triggered, or failed for more than 7 days.

[Possible Solution]

The Atom feed has timestamp information already. For example:

```
<entry><title>kernel-model-sabre-focal #21 (stable)</title><link rel="alternate" type="text/html" href="http://10.228.68.60:8080/job/kernel-model-sabre-focal/21/"></link><id>tag:hudson.dev.java.net,2008:http://10.228.68.60:8080/job/kernel-model-sabre-focal/</id><published>2021-04-02T11:52:46Z</published><updated>2021-04-02T11:52:46Z</updated></entry>
```

and the current parser shows:

```
[kernel-model-sabre-focal #21 (stable)](http://10.228.68.60:8080/job/kernel-model-sabre-focal/21/)
```

May be we could display like this instead:

```
[kernel-model-sabre-focal #21 (stable)(run N days ago](http://10.228.68.60:8080/job/kernel-model-sabre-focal/21/)
```