Add a configurable truststore for A1 adapter

The default truststore truststore.a1.adapter.jks contains a1simulator's cert from ORAN-SC:
https://gerrit.o-ran-sc.org/r/gitweb?p=sim/a1-interface.git;a=blob;f=near-rt-ric-simulator/certificate/cert.crt;h=51e37a79a508242a2179f0607df61fb795e94a6a;hb=refs/heads/master
This truststore can be overridden by mounting a new volume in docker-compose/helm,
and the correpoding password for the truststore is set using an environment variable.

Change-Id: Iec489a5a8f0435191475db0a1737e822f0a44b99
Issue-ID: SDNC-1339
Signed-off-by: RehanRaza <muhammad.rehan.raza@est.tech>