Add module to strip HTML tags (#7636)

Per https://issues.dp.la/issues/7636, this is a second stab at stripping HTML tags from a given record.

It seems best to implement this as a pipeline module, as is being done now.

It also seems best to try to strip all string fields, per Amy's comment in the ticket.

The pipeline module is applied initially to the Smithsonian profile, because issues with Smithsonian's titles prompted the creation of issue #7636.