Allow to render flame graphs from large files

[pablogsal]

Currently flamegraphs rendered from large capture files cannot be easily opened by browsers because there are tons of points in the memory over time plot and this causes the browser to hang. We should be able to just limit how many points are displayed in the plots to limit the size of the files and allow users to inspect very large capture files (or at least make it more possible).

[pablogsal]

Hopefully #491 helps with this