Add support for qualified symbols

[Mike-F362]

Qualified symbols (required by many ETSI specs to solve name collisions) lead to compiler errors.

Found ASN1 module ETSI-Common-Types.asn in directory
Found ASN1 module MainModule.asn in directory
Found ASN1 module Vendor-Types.asn in directory
Rasn compiler error:
Error matching ASN syntax at while parsing line 12 column 2.

Simplified example:

MainModule.asn

MainModule DEFINITIONS ::= BEGIN

IMPORTS
  Name FROM ETSI-Common-Types
    { itu-t(0) identified-organization(4) etsi(0) common-parameters(3280) version241(241) }

  Name FROM Vendor-Types
    { iso(1) org(3) dod(6) internet(1) private(4) enterprise(1) 99999 42 };

-- Naming collision is resolved by module prefix

ServiceA ::= SEQUENCE {
  name ETSI-Common-Types.Name
}

ServiceB ::= SEQUENCE {
  name Vendor-Types.Name
}

END

ETSI-Common-Types.asn

ETSI-Common-Types DEFINITIONS ::= BEGIN

Name ::= IA5String

END

Vendor-Types.asn

Vendor-Types DEFINITIONS ::= BEGIN

Name ::= UTF8String

END