Advert parsing: improvements

[sapristi]

• when single item, include title in shown advert
• when single item, remove paragraphs with <= n words not containing a price (n to find).
• table item: remove empty cols
• take number of items in title into account

[sapristi]

Adverts with bugs:

• https://www.reddit.com/r/mechmarket/comments/ugzusd/usaz_h_built_freyr_tkl_w_gat_inks_w_paypal_local/ : only price paragraph taken