[IDM.TRAIN.00016] Trusted Content Resolver - Trust Discovery Implementation

#9 (closed) - just basic flow implemented:

• DNS resolution from PTRs (no DNSSEC, no recursion yet)
• DID resolution -> DID Docs, service endpoints
• VC resolution from SEP (no VC verification yet)
• TL resolution from VC trustListURI (TL parse only, no TL validation yet)
• eu.xfsc.train.tcr.server.legacy package contains legacy code, don't review it..