Fix reply regex again

pipeline.yml is no longer used

fix Dockerfile

fix startup without sentry config

Discard old PM rooms

Co-Authored-By: Travis Ralston <travpc@gmail.com>

See https://github.com/matrix-org/pipelines/tree/master/matrix-appservice-irc

This actually respects config.sentry.enabled and thus makes the
bridge usable without configuring sentry.

Before config.schema.yml was missing in the image, because conf.* was
listed in the .dockerignore
This commit uses explicit names instead of `COPY .` and thus makes it
more readable (because everything is contained in the Dockerfile),
better cacheable and fixes the missing config.schema.yml

Fixes for DB migration script

Handle replies that contain displaynames

Speed up userReap by not syncing rooms

Increase default txn payload size limit and allow it to be configurable

Perform membership operations linearly