Improv/mass scanner results

Fixes

totalPagesScanned inaccurate.
browser crash on non headless sitemap scan.
scanned urls missing on report.
changed logic to add custom flow overlay before page load.
fixed allIssues startTime(previously it was referencing the end time instead of start time).
pages scanned inaccurate on desktop - solution: instead of updating completion guiInfoLog after runAxeScript in Crawl Domain, update it only when urlsCrawled.scanned.push. This is to prevent updating of guiInfoLog when scanned pages have reached maxRequestPerCrawl limit.

Detect if website has a sitemap and if so, scan the sitemap links based on descending chronological order and also, scan links with user input url path first. Subsequently, if pages scanned < p, run crawl domain from user input url.
if sitemap not detected, run crawl domain as per normal.

added logic for collecting data for mass scanner.
shifted wcagPercentage & wcagLinks from ejs to js so that mass scanner can access it.
(only if running from mass scanner mode) edited silentLogger to show error in console - so that all errors can be tracked for mass scanner.
(only if running from mass scanner mode) resultFileName add a 3 digit random number at back to prevent duplicate. - to handle cases where 2 scans create result file at the same time hence naming will clash.
(only if running from mass scanner mode) do not delete cloned browser profiles in backend - shifted deletion to mass scanner script instead.

[x] I've kept this PR as small as possible (~500 lines) by splitting it into PRs with manageable chunks of code
[x] I've requested reviews from 1 reviewer
[x] I've tested existing features (website scan, sitemap, custom flow) in both node index and cli
[x] I've synced this fork with GovTechSG repo
[ ] I've added/updated unit tests
[ ] I've added/updated any necessary dependencies in package[-lock].json npm audit, portable installation on GitHub Actions