[FEATURE] Results highlighting: Make number of snippets configurable in TypoScript

[thomasrawiel]

Currently, the number of fragments is hard coded in the

ext-solr/Resources/Private/Solr/configsets/ext_solr_12_0_0/conf/solrconfig.xml

Line 155 in f528685

<int name="hl.snippets">3</int>

Describe the solution you'd like
Please make the max number of fragments configurable in TypoScript, e.g.
plugin.tx_solr.resultsHighlighting.snippets = 3

Additional context
Solr Highlighting hl.snippets

solarium HighlightingTrait

Target versions
12, main

[dkd-kaehm]

@thomasrawiel Thanks for that issue.
I changed the description to same conventions/namings like Apache Solr it uses, we must prevent the expression-chain and complexety.