Added Caliper annotations for Laghos solver Serial version

[amroakmal]

Added Caliper annotations around the timed sections of the Serial Laghos Solver

[amroakmal]

@rfhaque @michaelmckinsey1 Please review. The goal is to add Caliper annotations for the serial Laghos version.

[rfhaque]

@amroakmal This looks good to me

[vladotomov]

@amroakmal @rfhaque I'm not sure what's the purpose here, but keep in mind that the code in /serial has not been kept in sync with the top directory for a long time. How are you using this and do you expect it to behave the same way as the baseline parallel Laghos?

[amroakmal]

We experimented running the serial code and confirmed that its not executed at all, we tested across the eight different Laghos problems. Attached are Caliper call-trees. Closing this PR.
FYI @slabasan @michaelmckinsey1 @rfhaque