Feature/Clear Arasaac db

[RodriSanchez1]

On this PR:

• Generat a static URL in the case that the tile was selected from the idb and is no internet conecction.
• Two buttons for download and delete the indexed database were added on the Symbols section. NOTE: The idb will not be deleted, just cleared.
• Improve the error handlers. This will prevent if exist an error while downloading the package or while processing.
• A signal controller was added on the arasaac file request, to avoid memory leaks if the user goes back while the download is active.

close #1529

[martinbedouret]

this is well implemented, anyway I don't see it is working. I just turn off the connection during the download but nothing happens.

[RodriSanchez1]

This works when you go back to the last history page while downloading. Without this implementation you will see a memory leak error.