Add units to plotters

[naik-aakash]

Closes #135

Updates

1. Added missing units (eV) to statics and interactive plots when COHP or ICOHP are plotted
2. Update corresponding test and reference test files

Note: It would be better to merge this PR before others so that I can resolve merge conflicts arising due to changes in this PR

[JaGeo]

Looks all great:

One thing, the interactive plotter seems to lose its energy label

lobsterpy automatic-plot-ia leads to:

lobsterpy automatic-plot-ia --label-resolved adds E-Ef but no (eV)

[JaGeo]

I left comments about my outputs. I am not sure why this is happening but this would need to be fixed before I can merge.

Thanks!

[naik-aakash]

lobsterpy automatic-plot-ia --label-resolved

Thanks for spotting this error. I Have fixed the issue now. It was partly a limitation of plotly not being able to render text when added to the latex labels. It should work fine now . Will push the changes in few minutes

[naik-aakash]

Fixed output

[naik-aakash]

I hope now it could be merged 😃

[JaGeo]

Unfortunately, lobsterpy automatic-plot-ia --label-resolved doesn't work anymore... Could you check?

[JaGeo]

It also stopped working in the master branch. Not sure why and when.