Fix flakiness in the UTs caused by the user_directory being updated in the
background

what could possibly go wrong

- allows sysadmins the ability to lock down their servers so that people can't
send their users room invites.

Instead of every time a new email pusher is created, as loading jinja2
templates is slow.

Allows delegating the password auth to an external module. This also
moves the LDAP auth to using this system, allowing it to be removed from
the synapse tree entirely in the future.

Wrap the `Requester` constructor with a function which provides sensible
defaults, and use it throughout

Use the pure-python ldap3 library, which eliminates the need for a
system dependency.

Offer both a `search` and `simple_bind` mode, for more sophisticated
ldap scenarios.
- `search` tries to find a matching DN within the `user_base` while
  employing the `user_filter`, then tries the bind when a single
  matching DN was found.
- `simple_bind` tries the bind against a specific DN by combining the
  localpart and `user_base`

Offer support for STARTTLS on a plain connection.

The configuration was changed to reflect these new possibilities.

Signed-off-by: Martin Weinelt <hexa@darmstadt.ccc.de>

Otherwise it tries to start the remote public room list updating looping call which breaks.

 - Add unittests for client, api and handler

Signed-off-by: Negar Fazeli <negar.fazeli@ericsson.com>

Signed-off-by: Patrik Oldsberg <patrik.oldsberg@ericsson.com>

This will enable more detailed decisions

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.

This reduces our ~8 second sequential test time down to ~7 seconds

Removes device_id and ClientInfo

device_id is never actually written, and the matrix.org DB has no
non-null entries for it. Right now, it's just cluttering up code.

This doesn't remove the columns from the database, because that's
fiddly.