LoadOrGenerateCertificate() takes two file path arguments, but then
uses the locations package to determine the actual path. Fix that
with a minimally invasive change, by using the arguments instead.
Factor out GenerateCertificate().
The only caller of this function is cmd/syncthing, which passes the
same values, so this is technically a no-op.
* lib/tlsutil: Make storing generated certificate optional. Avoid
temporary cert and key files in tests, keep cert in memory.
* add skeleton for lib/syncthing
* copy syncthingMain to lib/syncthing (verbatim)
* Remove code to deduplicate copies of syncthingMain
* fix simple build errors
* move stuff from main to syncthing with minimal mod
* merge runtime options
* actually use syncthing.App
* pass io.writer to lib/syncthing for auditing
* get rid of env stuff in lib/syncthing
* add .Error() and comments
* review: Remove fs interactions from lib
* and go 1.13 happened
* utility functions
Jakob Borg
André Colomb
Simon Frei