Forwarding history issues

[rkfg]

@hieblmi I found multiple issues with the new tab:

• columns are not aligned properly if there are emojis in the alias (see my code for columns in other tabs):
  
• aliases are justified by the left side in other tabs but here they're justified by the right side
• this tab loads really slowly, takes about a minute on RPi, I limited the number of records to 1024 and start time is -12h. I think it shouldn't take this long if data is cached properly, last 1024 events are returned instantly with lncli fwdinghistory --max_events 1024
• Enter does nothing here:
• lntop crashes on startup if [views.fwdinghist] section doesn't exist in the config, not a good UX for people who've just updated the binary but not the config; I guess populating the options with sane defaults would be nice

[hieblmi]

Thanks @rkfg for summarizing your findings. I will get to them in a bit.

[hieblmi]

Fixed the slowness issue here: #113