Encode UTF8 chars in document names

[raucao]

Currently, it does the wrong requests with unencoded characters.

[gregkare]

Right now the "é" (e with acute accent) is sent by rs-backup as \xE9 as part of a URL. The RS.js library encodes that as \xC3\xA9 when performing the PUT request, which is valid hex encoded UTF-8 (https://unicode-table.com/en/00E9/)

Typing "\xE9" in a node REPL results in the e with acute accent character, but that doesn't appear to be a valid encoded version of the U+00E9 unicode character

[gregkare]

Request from rs-backup: /gk-test-2018-04-12/myfavoritedrinks/bois-band\xE9
Request from myfavoritedrinks: /gk-test-2018-04-12/myfavoritedrinks/bois-band\xC3\xA9

[gregkare]

And there's a site using the utf8 npm module to encode/decode utf8: https://mothereff.in/utf-8#%C3%A9