Renames ``load_config`` to ``load_or_generate_config``
Adds a method called ``load_config`` that just loads the
config.
The main synapse.app.homeserver will continue to use
``load_or_generate_config`` to retain backwards compat.
However new worker processes can use ``load_config`` to
load the config avoiding some of the cruft needed to generate
the config.
As the new ``load_config`` method is expected to be used by new
configs it removes support for the legacy commandline overrides
that ``load_or_generate_config`` supports
synapse
This is necessary for replicating the data in synapse to be visible to a
separate service because presence and typing notifications aren't stored
in a database so won't be visible to another process.
This API can be used to either get the raw data by requesting the tables
themselves or to just receive notifications for updates by following the
streams meta-stream.
Returns updates for each table requested a JSON array of arrays with a
row for each row in the table.
Each table is prefixed by a header row with the: name of the table,
current stream_id position for the table, number of rows, number of
columns and the names of the columns.
This is followed by the rows that have been added to the server since
the requester last asked.
The API has a timeout and is hooked up to the notifier so that a slave
can long poll for updates.
Currently we store all access tokens in the DB, and fall back to that
check if we can't validate the macaroon, so our fallback works here, but
for guests, their macaroons don't get persisted, so we don't get to
find them in the database. Each restart, we generate a new ephemeral
key, so guests lose access after each server restart.
I tried to fix up the config stuff to be less insane, but gave up, so
instead I bolt on yet another piece of custom one-off insanity.
Also, add some basic tests for config generation and loading.
