Harden the Jelly parsers against hostile inputs

[Ostrzyciel]

• Add null checks and catch some other exceptions to throw prettier errors. These checks are free because the JVM inserts them anyway.
• Limited number of rows per frame in Jelly-SPARQL to mitigate an OOM DoS vector.
• Add tests for specific known hostile inputs.
• Add fuzzing tests for the decoder.

Only the sparql decoder was susceptible to an OOM DoS (good, it was not even released yet). The rest were just throwing ugly exceptions.

[codecov]

Codecov Report

❌ Patch coverage is 93.75000% with 3 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
.../neverblink/jelly/core/internal/DecoderLookup.java	78.57%	3 Missing ⚠️

Files with missing lines	Coverage Δ	Complexity Δ
...nk/jelly/core/patch/internal/PatchDecoderImpl.java	97.45% <100.00%> (+3.98%)	46.00 <15.00> (+5.00)
...jelly/core/sparql/JellySparqlConverterFactory.java	100.00% <100.00%> (ø)	4.00 <2.00> (+1.00)
.../jelly/core/sparql/internal/SparqlDecoderImpl.java	100.00% <100.00%> (ø)	74.00 <0.00> (+1.00)
.../jelly/core/sparql/internal/SparqlEncoderImpl.java	99.46% <100.00%> (ø)	111.00 <5.00> (ø)
...everblink/jelly/core/internal/NameDecoderImpl.java	83.95% <100.00%> (+1.51%)	13.00 <0.00> (+1.00)
...verblink/jelly/core/internal/ProtoDecoderImpl.java	97.26% <100.00%> (+4.95%)	28.00 <0.00> (+4.00)
...k/jelly/convert/jena/sparql/RowSetReaderJelly.java	81.15% <100.00%> (+1.15%)	11.00 <0.00> (ø)
...onvert/rdf4j/sparql/AbstractJellySparqlParser.java	86.20% <100.00%> (+0.75%)	9.00 <0.00> (ø)
...onvert/rdf4j/sparql/JellySparqlParserSettings.java	100.00% <100.00%> (ø)	2.00 <0.00> (ø)
.../neverblink/jelly/core/internal/DecoderLookup.java	86.36% <78.57%> (+6.36%)	5.00 <2.00> (+2.00)

... and 2 files with indirect coverage changes

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