Adding root histogram example to analyze pane

@uplegger -- Again from @masizemo who we will soon start having making these MRs directly.

• Added histogram plotting directly into analyze pane. Still need to decide what plot is most useful and when/how this pane should be updated.
• Some cleanup

See https://gitlab.cern.ch/UTKCMS/ModuleScorecard/-/merge_requests/8 for more details.

assigned to @uplegger

added 4 commits

• ea247b33 - 1 commit from branch cms_tk_ph2:develop
• e9241ddf - Merge branch 'develop' of https://gitlab.cern.ch/cms_tk_ph2/ModuleScorecard into develop
• 0cfef137 - Removed temp comments from RootCanvas.cxx
• 2f911e47 - Merge branch 'dev/analyzerPlot' into 'develop'

Compare with previous version

mentioned in commit 650f148e

merged