Mi: add mi support for lttng struct

Add mi-lttng support to the following struct:
    lttng_domain
    lttng_channel
    lttng_channel_attr
    lttng_event
        +multiple mi utility format:
            common attribute
            tracepoint_loglevel
            tracepoint_no_loglevel
            function probe
            function entry
    lttng_event_field

mi-lttng other element
    pid element

Rebase on master:
Fix: remove extra linking due to add of mi-lttng to libcommon
Mi: support for command list
Mi: mi xsd validation

Command list and version supported
Mi version command: add commit version to mi version