[Core] Use null safe-messages

[mpkorstanje]

With cucumber/common#1879 messages now uses
Optional<T> for optional types avoiding some unexpected null references.
This resulted in some updating of gherkin and html-formatter.

Additionally with this change the dependency on Jackson has been removed from
messages. However we still have to serialize the message objects into json.
So for now Jackson is shaded into core instead. And eventually we'll be able
to spin this out to it's own module.

[codecov]

Codecov Report

Merging #2497 (20f1f9d) into main (655eb1f) will increase coverage by 0.60%.
The diff coverage is 97.92%.

@@             Coverage Diff              @@
##               main    #2497      +/-   ##
============================================
+ Coverage     83.80%   84.40%   +0.60%     
+ Complexity     2651     2648       -3     
============================================
  Files           309      310       +1     
  Lines          9360     9324      -36     
  Branches        913      896      -17     
============================================
+ Hits           7844     7870      +26     
+ Misses         1183     1121      -62     
  Partials        333      333              

Impacted Files	Coverage Δ
...ava/io/cucumber/core/plugin/TimelineFormatter.java	90.57% <ø> (ø)
...ber/core/gherkin/messages/GherkinMessagesStep.java	61.53% <80.00%> (ø)
...ucumber/core/options/CommandlineOptionsParser.java	80.23% <85.71%> (+37.03%)	⬆️
...main/java/io/cucumber/core/runner/CachingGlue.java	98.15% <96.96%> (-0.95%)	⬇️
...in/java/io/cucumber/core/plugin/HtmlFormatter.java	77.77% <100.00%> (+1.30%)	⬆️
...src/main/java/io/cucumber/core/plugin/Jackson.java	100.00% <100.00%> (ø)
...in/java/io/cucumber/core/plugin/JsonFormatter.java	73.62% <100.00%> (ø)
...java/io/cucumber/core/plugin/MessageFormatter.java	85.71% <100.00%> (ø)
...java/io/cucumber/core/plugin/TestSourcesModel.java	83.20% <100.00%> (+1.31%)	⬆️
...n/java/io/cucumber/core/plugin/UsageFormatter.java	57.14% <100.00%> (ø)
... and 15 more

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[aslakhellesoy]

Very nice!!