Implement chat feature

features/config.exs

features/contexts/messaging_context.exs

features/contexts/navigation_bar_context.exs

features/messaging.feature

features/navigation_bar.feature

lib/proptrackr/accounts/user.ex

lib/proptrackr/messaging/message.ex

lib/proptrackr/messaging/message_association.ex

lib/proptrackr_web/controllers/chat_controller.ex

lib/proptrackr_web/controllers/chat_html.ex

lib/proptrackr_web/controllers/chat_html/index.html.heex

lib/proptrackr_web/controllers/chat_html/new.html.heex

...proptrackr_web/controllers/properties_html/show.html.heex

lib/proptrackr_web/router.ex

priv/repo/migrations/20241204150453_add_messages.exs

test/proptrackr_web/controllers/chat_controller_test.exs