DEMRUM-2304: remove force try for regex compilation

[carlosmcevilly]

DEMRUM-2304: remove force try for regex compilation

Previously this work did not have a ticket, so it has been re-pushed with amended commit messages to now include the ticket number.

Main change is to remove try! usage in regex compilation code in addLinkToSpan(::)

• restructure to guard let regex =
• introduce log statements for failures: one serious (.fault), one not (.debug)
• add intentional breaking hard failure if regex does not compile. This must be caught early. The objection is we have a hard coded regex; how could it go wrong? And the answer is, of course, editing.
• update the regex to remove the backslashes for double quotes -- although the quotes are nested, this is fine in swift ## regular expression syntax. If I am wrong we will have a preconditionFailure very soon.
• add truncation to the logged string for the .debug log because we get that string from an external source
• add another guard when extracting the traceId and spanId
• move the regex into the function as it's only used in that scope
• re-enable the lint check for SplunkNetwork in both included app projects
• fix a docs link issue to pass pre-merge checks

[SMickelsn]

Looks good.