moved sparql related documentation content

docs/guides/sparql/about-sparql.md

docs/guides/sparql/intro.md

docs/guides/sparql/introduction.mdx

docs/guides/sparql/virtuoso-sparql.md

sidebars.ts

static/img/SPARQL-query1-sample-results.png

static/img/fct-hzdr-results-ex.png

static/img/fct-hzdr-results.png

static/img/fct-hzdr.png

static/img/fct-lookup.png

static/img/fct-uri-lookup.png

static/img/fct.png