Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/746

ma1sd requires the openid endpoints for certain functionality.
Example: 90b2b5301c/src/main/java/io/kamax/mxisd/auth/AccountManager.java (L67-L99)

If federation is disabled, we still need to expose these openid APIs on the
federation port.

Previously, we were doing similar magic for Dimension.
As per its documentation, when running unfederated, one is to enable
the openid listener as well. As per their recommendation, people
are advised to do enable it on the Client-Server API port
and use the `federationUrl` variable to override where the federation
port is (making federation requests go to the Client-Server API).

Because ma1sd always uses the federation port (unless you do some
DNS overwriting magic using its configuration -- which we'd rather not
do), it's better if we just default to putting the `openid` listener
where it belongs - on the federation port.

With this commit, we retain the "automatically enable openid APIs" thing
we've been doing for Dimension, but move it to the federation port instead.
We also now do the same thing when ma1sd is enabled.

A bit late, but still better than nothing.

Related to #681 (Github Pull Request)

Fixes #696 (Github Issue)

Fixes #685 (Github Issue).

Related to 23daec748c and #662 (Github Issue).

Fixes #562 (Github Issue)

Fixes #586 (Github Issue)

Related to #557 (Github Pull Request).

Related to #540 (Github Pull Request).

Related to #551 and #555 (Github Pull Requests).

We can undo this once https://github.com/ma1uta/ma1sd/issues/44 gets
resolved.

Note the potential breaking change

Resolves #474

Related to #454 (Github Pull Request).

Related to #436 (Github Pull Request).

Related to #425 (Github Pull Request).

Related to #386 (Github Pull Request)

Related to #339 (Github Pull Request).

Prompted by: https://matrix.org/blog/2019/11/09/avoiding-unwelcome-visitors-on-private-matrix-servers

This is a bit controversial, because.. the Synapse default remains open,
while the general advice (as per the blog post) is to make it more private.

I'm not sure exactly what kind of server people set up and whether they
want to make the room directory public. Our general goal is to favor
privacy and security when running personal (family & friends) and corporate
homeservers, both of which likely benefit from having a more secure default.