Added 'Last Transfer' date in torrents details: list, modal, UI column settings

[gboudreau]

Description

Added 'Last Transfer' date in torrents details: list, modal, UI column settings

Note: Requires rTorrent configuration to save d.custom.last_xfer:

## SCHEDULE: Set "last_xfer" custom timestamp field for items that transfer data
method.insert.value = pyro.last_xfer.min_rate, 5000

method.insert = pyro._last_xfer_check_min_rate, simple|private,\
    "greater=argument.0=,pyro.last_xfer.min_rate="
method.insert = pyro._last_xfer_update, simple|private,\
    "d.custom.set=last_xfer,$cat=$system.time= ; branch=argument.0=,d.save_resume="
method.insert = d.last_xfer.is_active, simple,\
    "or={pyro._last_xfer_check_min_rate=$d.up.rate=,pyro._last_xfer_check_min_rate=$d.down.rate=}"
method.insert = d.timestamp.last_xfer, simple, "if=$d.last_xfer.is_active=,$cat=$system.time=,$d.custom=last_xfer"

schedule2 = pyro_update_last_xfer, 33, 17,\
    "d.multicall2=active,\"branch=$d.last_xfer.is_active=,pyro._last_xfer_update=\""

Motivation and Context

I wanted to be able to identify torrents which had no activity for a while, to remove them first.

How Has This Been Tested?

Used Flood with this change for months...

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.