Add torrent hash in search plugins

[ngosang]

I'm able to get the torrent hash from most search engines so we can implement these features:

• Group search results by hash
• Add an "Already downloading" column in search result

I'm also able to do it in a manner that old plugins (unofficial) still works in new qbittorrent. And the new plugins (with hash support) works in old qbittorrent versions.

I can do the change in search plugins and the change need in novaprinter.py. There is no need to change the c++ code, but would be nice if you add a new column with the hash.
Now, nova2.py returns (desc_link is optional):

link|name|size|seeds|leech|engine_url|**desc_link**

Whit the changes will be (all compulsory, but last 2 can be empty):

link|name|size|seeds|leech|engine_url|desc_link|hash

What do you think? @Chocobo1 @sledgehammer999 @Piccirello @zeule

[nindogo]

In some cases to get the hash you may have to go into the desc_link. If there were say 300 results that may take time, even threaded, and appear slow no?

Maybe I am wrong and users may be OK with a little bit longer delay in exchange of not having 2 identical torrent results?

[ngosang]

In some cases to get the hash you may have to go into the desc_link. If there were say 300 results that may take time, even threaded, and appear slow no?

I'm not going to do that. In most search engines (all but 1337x) I can get the hash from the main page. If it's not in the main page I will leet the hash as "Unknown".

[rmlrml]

Just a user here. I came searching the github issues to see if hash column in the search tab was already a requested feature. I personally was just hoping for a hash column, didn't think of or care about grouping duplicate results of the same torrent into one row.

I often will try to sort by size column or name column just to gather multiple results of the same torrent together, then download all of them just in case one has trackers that the others don't. But sizes aren't always reported exactly the same by each engine, and names are often different. If there were a hash column I could just sort by that, select all of the results having the same hash and click download.