Allow tracking of old bills to alert if they are reintroduced

[GPHemsley]

It used to be that you could track bills from Congresses that were not the current one. This seems to have been disabled, presumably because bills from old Congresses are not likely to generate new alerts.

However, it could be useful to track old bills in order to be alerted if related/similar bills are introduced in later Congresses.

[GPHemsley]

It seems this was implemented at some point? It is now possible to add older bills to lists, and the trackers will fire if the bill is reintroduced in a later Congress.