feat: enhance parser to handle time for some events without an end event (workflow + visualforce)

[lcottercertinia]

Is your feature request related to a problem?

Some events take time but have no specific end event e.g WF_APPROVAL_SUBMIT + WF_NEXT_APPROVER
I would like to see them on the timeline somehow.

Describe the solution you'd like

Improve the log parser to show time taken for more events without a specific end
e.g WF_APPROVAL_SUBMIT + WF_NEXT_APPROVER events.
WF: This is just about anything within the code unit workflow or start with WF_

VF: This also happens to some of the events for visualforce, they start with VF_
There may be some handling for VF_PAGE_MESSAGE we can do too

To get some of this to work we may have to do a second parse once the events have become child events of another.
This is because we can always use the end time of the parent of the start time of the next event as a fallback when inferring the end time

Some events do not seem to have an exit but do take up time I would like to see them reflect on the timeline
An example here would be WF_APPROVAL_SUBMIT events and basically any event within the code unit workflow

Describe the solution you'd like

I know this might be tricky and it would be great to get SF to add an end however the next best would be to use the next event along as the end time. e,g for a WF_APPROVAL_SUBMIT event the next WF_APPROVAL_SUBMIT might be the end stamp.