READY: Set active downloads/seeds to unlimited

[qstokkink]

Related to #6801

This PR:

• Updates active_downloads and active_seeds to be unlimited by default (capped to 500 in total by libtorrent internally).

This seems like a better default than a max of 3 downloads and 5 seeds.

A follow-up PR should make this configurable in the GUI.

[egbertbouman]

I think these settings apply to auto-managed downloads. Are downloads auto-managed nowadays?

[qstokkink]

I believe so, from the docs:

By default, torrents are auto-managed, which means libtorrent will pause, resume, scrape them and take them out of upload-mode automatically.

[egbertbouman]

But isn't the flag cleared by:

tribler/src/tribler/core/libtorrent/download_manager/download.py

Lines 284 to 288 in 79a1509

	# In LibTorrent auto_managed flag is now on by default, and as a result
	# any torrent"s state can change from Stopped to Downloading at any time.
	# Here we unset this flag to prevent auto-resuming of stopped torrents.
	if hasattr(self.handle, "unset_flags"):
	self.handle.unset_flags(lt.add_torrent_params_flags_t.flag_auto_managed)

[qstokkink]

Indeed it is.

The auto managed flag IS deprecated. So, just to be sure, I double-checked whether libtorrent somehow automatically enabled auto managing anyway. This does not seem to be the case. I can download more than 3 torrents at the same time:

I guess the original issue was then already resolved at some point. So, I will close that.