Raw download and filename character code

[toras]

Hello.

In Kallithea 0.7.0, there was a problem when raw downloading the file in the repository from the web interface.
It seems to be an error if the filename registered in the repository cannot be encoded with 'latin-1'.
It's not a big issue, as you can work around the problem by cloning the repository, but I'll report it here.

When an error occurs, the following will be displayed on the browser.
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Internal Server Error
The server encountered an unexpected internal server error
(generated by waitress)
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In addition, the following traceback is output to the console.
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Traceback (most recent call last):
   File "/home/kallithea/.local/lib/python3.8/site-packages/waitress/channel.py", line 350, in service
     task.service()
   File "/home/kallithea/.local/lib/python3.8/site-packages/waitress/task.py", line 171, in service
     self.execute()
   File "/home/kallithea/.local/lib/python3.8/site-packages/waitress/task.py", line 479, in execute
     self.write(chunk)
   File "/home/kallithea/.local/lib/python3.8/site-packages/waitress/task.py", line 311, in write
     rh = self.build_response_header()
   File "/home/kallithea/.local/lib/python3.8/site-packages/waitress/task.py", line 284, in build_response_header
     return tobytes(res)
   File "/home/kallithea/.local/lib/python3.8/site-packages/waitress/compat.py", line 69, in tobytes
     return bytes(s, "latin-1")
UnicodeEncodeError: 'latin-1' codec can't encode characters in position 84-85: ordinal not in range(256)
----

Thanks

--
toras9000