timeline: optionally show component of tickets.
timeline: optionally show component of tickets.

If the `[timeline] ticket_show_component` setting is set to a true
value, each ticket entry in the timeline will show the //component//
of the ticket, prefixed to the ticket's summary.

Patch contributed by Thomas Akesson <thomas.akesson@fastmail.fm>,
thanks!

Closes #10885.


git-svn-id: 0d96b0c1a6983ccc08b3732614f4d6bfcf9cbb42@11411 af82e41b-90c4-0310-8c96-b1721e28e2e2

rbaumg/trac,rbaumg/trac,rbaumg/trac,rbaumg/trac