Rename package name for messages for AutowareArchitectureProposal packages

[mitsudome-r]

Currently, names of the messages used for Autoware Architecture Proposal packages could overlap with AutowareAuto msgs.
We will replace the package name with unique packages name (e.g. t4_planning_msgs) after all the merging of packages are done.

[tkimura4]

https://github.com/autowarefoundation/autoware.universe/blob/a330c08a9e3e20748bf36d488bd3a70a7c142ab4/messages/README.md
The description of Readme may need to be changed according to this change.

[tkimura4]

#150

[tkimura4]

PR merged.