SPARQLStore / QE / Split conditions, add SparqlConditionBuilder

- Individual condition are moved from `SMWSparqlStoreQueryEngine`
- Condition building has been moved into its own component to aid SRP
- `SparqlConditionBuilder::buildCondition` now takes in a Description and outputs a sparql where condition

Integration with [QE][#375] is done a follow up, otherwise the PR becomes to large and this PR only consists of copied code + additional newly created tests `SparqlConditionBuilderTest`