Fix minor job log issues, update decorations, add new tree view badge

[SanjulaGanepola]

Fixes

• https://github.com/IBM/vscode-ibmi-projectexplorer/issues/496
• https://github.com/IBM/vscode-ibmi-projectexplorer/issues/509
• https://github.com/IBM/vscode-ibmi-projectexplorer/issues/492
• Fix update to .gitignore adding unnecessary newlines if there are no entries to add
• Add missing variable error decoration tooltips

Enhancements

• Add a view badge on the job log which shows the number of failed objects (if there is a local joblog.json) for the active project
• Add severity level as a decoration if it is >=10 (includes a badge and tooltip) so the user knows what severity level is set

[SanjulaGanepola]

@edmundreinhardt Should we be referring to them as "Failed Jobs" or "Failed Objects"? The view badge text currently says "X Failed Objects". But our toggle action uses the words "Show Failed Jobs". What should the wording be?

@irfanshar Could you help with manually testing this PR?

[edmundreinhardt]

Failed objects

@edmundreinhardt Should we be referring to them as "Failed Jobs" or "Failed Objects"? The view badge text currently says "X Failed Objects". But our toggle action uses the words "Show Failed Jobs". What should the wording be?

@irfanshar Could you help with manually testing this PR?

failed objects