Allow to open single process from perf.data in a separate window

[GitMensch]

Is your feature request related to a problem? Please describe.
Collecting data via perf -a can easily get a lot of processes traced and after seeing the overall consumption / use it is most common to inspect part of the data (where biggest hotspots are). Opening a single process of the combined data would be very helpful in this case.

Describe the solution you'd like
Ideally both:
1 Timeline view: addition of a context menu entry to the Process entries -> open in separate Hotspot instance
2 the option on opening to first list only collected processes (with all data available, which ideally would be: PID, binary, command line options, but I don't know if those are available in the tracing #430), ideally with a filter like in the timeline (that would for example allow to just filter for a single interesting binary or a bunch of binaries in a folder).

Describe alternatives you've considered
As I do now: variant of solution 1: use "filter in on process".

Additional reasons that 1 and 2 would be useful
1 the new instance would allow to open multiple instances to inspect multiple processes, "filter in on process" only allows one, then you need to reset the filter, then search for the next interesting, ...
2 filtering on a process (or a list of them) on open should allow to open much bigger recordings much faster (even if the filtering is only applied by "skipping")
1+2: would likely reduce the number of warnings and errors in stderr and in the summary as one would filter to processes that has the necessary debugging information; additional this possibly solves the #290 issue as each process (in each instance) would only open the symbols that are interesting - and not for half the system

[GitMensch]

I guess this would be a filter that would be applied in perfparser to limit data of a recording to one process (see #475) and then this could be implemented in hotspot?