Add sync log to GUI

Recording dedicated sync log entries in a ring buffer. From within the
library page, the user can view the log and copy the contents (as JSON
string) to the clipboard).
17 jobs for 120-improve-error-reporting-of-webdav-sync in 7 minutes and 2 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Images
manual #41846165
allowed to fail manual
build_image_fedora
manual #41846166
allowed to fail manual
build_image_fedora_system
manual #41846167
allowed to fail manual
build_image_ubuntu
manual #41846168
allowed to fail manual
build_image_win32
manual #41846169
allowed to fail manual
build_image_win64
 
  Build
passed #41846170
linux_builtin

00:03:28

passed #41846171
linux_system

00:03:42

manual #41846177
macos allowed to fail manual
macos
passed #41846172
ubuntu_appimage

00:05:04

passed #41846173
win32_build

00:04:01

manual #41846175
windows allowed to fail manual
win32_vs_build
passed #41846174
win64_build

00:03:40

manual #41846176
windows allowed to fail manual
win64_vs_build
 
  Installer
passed #41846178
win32_installer

00:01:56

manual #41846180
allowed to fail manual
win32_vs_installer
passed #41846179
win64_installer

00:01:51

manual #41846181
allowed to fail manual
win64_vs_installer