Support new bundle format

[alanpearce]

It seems that Codota have changed the download format for TabNine binaries. They are now distributed in zip files. source

These commits enable versions distributed in this format to be downloaded and installed correctly.

It assumes the user has unzip in their path. This might not be true on certain platforms, but upstream's downloader makes the same assumption.

[TommyX12]

Thanks for the PR. I noticed that the unzip assumption would make it difficult for Windows to obtain the binary. Seems like other backends (e.g. Vim, Sublime, VSCode) simply bundled the binaries within the plugin repo (the dl_binaries.sh isn't for the user to run). I remember when I tried to do the same, MELPA disliked having third party binaries contained within the plugin.
Is there a more universal way of unzipping zip files, or could we add a check for unzip in the path and notify the user when it's not available? Although seems like a cleaner solution can be achieved if Codota can help out.

[alanpearce]

There is archive-zip-extract, but that only extracts a single file specified by the second parameter.

I found a dired function that might make things more cross-platform, but I don't have a Windows machine set up, unfortunately. However, if dired-do-compress (default Z) unzips the contents of $FILE.zip to $FILE\, then this should work fine (the commit relies on the dired's behaviour of creating a directory with the basename of the archive as the root of the extracted files)

[TommyX12]

Did a small test on Windows, seems like the dired method does work; however, I think that dired still uses unzip under the hood, so not sure if that's truly cross-platform. Seems like there's no better way to deal with this for now as long as MELPA doesn't allow binary bundling and TabNine keep using zip as its binary format. Thanks for the PR.