"Let's encrypt" certificate issuer string changed within last 24hours remotely.
Update its name to make RAPPS stop complaining on DB update.
And also fix a bug in rapps mixing A()/W() in the
messagebox that informs about that cert check failure.
Fix is port of
0.4.15-dev-1120-g 12caaece25
0.4.15-dev-1617-g f77f5a30cf
Next time this happens I will relentlessly undefine CMakeLists.txt USE_CERT_PINNING
Due to infrastructure changes on 2018-02-17 (after initial 0.4.7rls)
we totally broke the rapps compatibility of all releases before 0.4.8
leaving rapps useless in those.
Therefore I decided to port back what is necessary to make rapps work
again also in this ancient release.
fixes CORE-14351 adapts to infrastructure changes
fixes CORE-14350 RAPPS Certificate pinning
fixes download from FTP
and merges many other improvements from GSOC 2017 back in time
