Replace the 157 fallbacks originally introduced in Tor 0.3.5.6-rc
in December 2018 (of which ~122 were still functional), with a
list of 148 fallbacks (70 new, 78 existing, 79 removed) generated
in June 2019.

Closes ticket 28795.

Note that we created extra lists from DE and US, but they didn't add
any more fallbacks when we tried to merge them.