Use more appropriate container (QList) for resume data queue buffer.
QVector in Qt5 has poor performance of the first element taking operation,
which is used to process the resume data queue. In Qt6, QVector is just an
alias for QList, so there was no problem there.
PR #18387.
Fixes#18341.
Reduce the total startup time of the application and maintain sufficient responsiveness of the UI during startup due to the following:
1. Load resume data from disk asynchronously in separate thread;
2. Split handling of loaded resume data in chunks;
3. Reduce the number of emitting signals.
PR #16840.
Implement ResumeDataStorage class as base for all "resume data" storages.
Implement BencodeResumeDataStorage class and put all existing logic of
"resume data" loading/saving there.
