[Front-end] SPARQL queries

[vancauwe]

SPARQL Queries to match the following main questions:

the data should be able to be filtered with a limited number of criteria :

• Metal (chemical)
• Reaction name
• Reaction type (e.g. photochemistry, electrochemistry...)
• CAS number / SMILE of one of the chemicals used during the reaction
• Upload date of data
• Solvent name
  Ideally these criteria should be able to be combined to define a final dataset that can be extracted and that receives a specific URL for further use.

Dependent on issues #2 #3 #8 #10 #11 #12 #13