Better rosbag naming (ie. adding some context)

[oswinso]

Right now, it is basically impossible to tell what each rosbag contains, ie.

jessii_JOHNSCREEK_2020-02-22-14-23-06.bag
jessii_JOHNSCREEK_2020-02-22-14-52-58.bag
jessii_JOHNSCREEK_2020-02-22-14-55-01.bag
jessii_JOHNSCREEK_2020-02-22-14-56-59.bag
jessii_JOHNSCREEK_2020-02-22-15-02-02.bag
jessii_JOHNSCREEK_2020-02-22-15-04-00.bag
jessii_JOHNSCREEK_2020-02-22-15-15-28.bag
jessii_JOHNSCREEK_2020-02-22-15-20-24.bag
jessii_JOHNSCREEK_2020-02-22-15-22-32.bag
jessii_JOHNSCREEK_2020-02-22-16-46-30.bag
jessii_JOHNSCREEK_2020-02-22-17-28-55_0.bag
jessii_JOHNSCREEK_2020-02-22-17-35-40_0.bag
jessii_JOHNSCREEK_2020-02-22-17-36-59_1.bag
jessii_JOHNSCREEK_2020-02-22-17-38-15_2.bag
jessii_JOHNSCREEK_2020-02-22-17-39-35_3.bag

I think one way of solving this would be to make rosbag.launch take in an arg that specifies some sort of context, say run1, so that it would result in something like

run1_jessii_JOHNSCREEK_2020-02-22-17-35-40_0.bag
run1_jessii_JOHNSCREEK_2020-02-22-17-36-59_1.bag
run1_jessii_JOHNSCREEK_2020-02-22-17-38-15_2.bag
run1_jessii_JOHNSCREEK_2020-02-22-17-39-35_3.bag

and hopefully it'll be easier to tell what we were trying to record with the bagfile.

AC: rosbag.launch saves some sort of context with the name.