Draft to use trust information to filter results - only lunr indexer

[enriquepablo]

• I have only updated the lunr indexer (not the redis one).
• The lunr indexer now has 2 more indexes: registrationAuthority and entityID.
• The search for the lunr indexer is more complex now: instead of looking for full text presence in all the indexes, it is possible to indicate which indexes to look in, and whether to include or exclude the matches.
• In addition to the JSON for the list of IdPs, the app now loads a JSON with the trust info, and keeps it in a dict / object keyed by (SP) entityID.
• In the search requests, apart from the q param, we can add 2 more params, entityID and trustProfile. With these, we get the corresponding trust info and use it to filter the list of IdPs.