DynamicTablesPkg: DynamicPlatRepo: Add TokenGenerator

DynamicTablesPkg: DynamicPlatRepo: Add TokenGenerator

The DynamicPlatRepo library allows to handle dynamically created
CmObj. The dynamic platform repository can be in the following states:
1 - Non-initialised
2 - Transient:
    Possibility to add CmObj to the platform, but not to query them.
3 - Finalised:
    Possibility to query CmObj, but not to add new.

A token is allocated to each CmObj added to the dynamic platform
repository (except for reference tokens CmObj). This allows to retrieve
dynamic CmObjs among all CmObj (static CmObj for instance).

This patch add the TokenGenerator files.

Signed-off-by: Pierre Gondois <Pierre.Gondois@arm.com>
Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>