Namespace and fixed size arrays fixes

[Rezenders]

Depends on PR #61

This PR introduces 2 fixes:

1. Generation of interface names with global scope in nodes with namespace
   For example, the topic /diagnostics published from the node /mavros/mavros would be generated as tics.

publishers:
        'tics':
          type: 'diagnostic_msgs/msg/DiagnosticArray'
          qos:
          # profile:
          # history: UNKNOWN
          # depth:
            reliability: reliable
            durability: volatile

2. Interfaces with arrays with fixed size would be generated with fixed size but the DSL doesn't support it.
   For example, AccelWithCovariance from geometry_msgs is translated as:

AccelWithCovariance
        message
            "geometry_msgs/msg/Accel" accel
            float64[36] covariance

However, the DSL doesn't support float64[36] only float64[].
I changed it to generate:

AccelWithCovariance
        message
            "geometry_msgs/msg/Accel" accel
            float64[] covariance