add needed type hints for phpunit8

This will break a lot of plugin tests, but can't be avoided

PHP8 fix part 5: Trying to access array offset on value of type bool/null

crlf 2 lf whitespace fixes

(incl. the refactored file)

refactor info functions test

pageinfo() test no longer required, unit test committed elsewhere and
verified against both previous and updated versions of pageinfo() fn.

basicinfo() and mediainfo()

refactor info functions test

pageinfo() test no longer required, unit test committed elsewhere and
verified against both previous and updated versions of pageinfo() fn.

basicinfo() and mediainfo() tests separated each into their own test
file.

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