added: additional monitors and status info for cpu freq and vram usage

[ProPuke]

This adds some displays for cpu frequency and vram usage on the indicator (I'm playing with amd-pstate at the moment, and wanted to be able to monitor the cpu freq on the fly)
I've also reordered them a little on the bar and added some separators in settings to hopefully group them a bit clearer.
I improvised a bit on the vram icon. Hopefully somebody else can improve or do something slight better.

I also added some more status bar items to show gpu and vram usage there.
While doing so I noticed that under nvidia the vram monitor wasn't actually showing percentage of vram usage, but fb usage. So I corrected that to show percentage of actual total vram in use, hopefully matching the intent and what happens under amd.

We also weren't ensuring gpu != null in one case (possible crash? :S) so I corrected that.

I've not done anything about i18n. I don't know how that works :D (Do I need to run a script of some kind to update the translation strings?)

[stsdc]

Thanks for the PR!
I'll try to check it thru the weekend.

[stsdc]

After building and installing, and restarting wingpanel I got this error for wingpanel

(io.elementary.wingpanel:128627): GLib-GIO-ERROR **: 23:36:46.129: Settings schema 'com.github.stsdc.monitor.settings' does not contain a key named 'indicator-temperature-state'

[stsdc]

Ok, obviously I had indicator build and installation disabled

[ProPuke]

As a note:

I removed indicator-temperature-state and instead replaced it with indicator-cpu-temperature-state and indicator-gpu-temperature-state
(there is still some commented code making ref to the old indicator-temperature-state, I probably should have tidied that, should you want to enable it for testing)

[stsdc]

Codewise and naming is ok. I will try to polish UI a bit and will merge it. Thanks a lot!

[ProPuke]

Cheers! Thank you

[stsdc]

I have removed vram from statusbar. It becomes too clunky IMO.
Need to consider if statusbar needs these cpu, ram etc at all if there is an Indicator

[ProPuke]

Maybe adding gpu stuff to the status bar was a bit too much.
Just cpu, ram and swap is likely enough if someone wants an at a glance summary on processes running (and I guess maybe gpu usage)
If they want more details they can funnel down into System and view more in-depth info there.
Yeah, I'd over-complicated it.

I'd still keep the status info there if indicators are on, though. If people expect something to be somewhere it should be there, even if they've enabled showing it somewhere else. Don't go against expectations.