New bundle/build + test framework and small improvements

• Test framework - from webpack manual setup to batr (Rollup, AvaJS, Playwright and Standard in one devDep)
• return item if no hits
• can do truncation on item even if no hits
• UI tests
• Fixing demo

More versatile and robust: cut-off and truncating and padding

• Able to cut off returned item if longer than itemMaxWords
• If so, tries to truncate to show all hits
• Possibility to choose how many words before and after a hit
• Joins highlighting if neighbour words
• If not all hits, then cuts off hits too

Fixing devDep security issues

Still minimist-issue left, waiting for upstream fix, but no problem with the actual package, since no dependencies.

Correcting documentation

query comes before item as input to the highlight function:
highlight(query, item, highlighting)

Ready for the browser

Got tests, browser tests and browser demo.