As we use `execute_values` with the `fetch` parameter.

Introduced in #9104 

This wasn't picked up by the tests as this is all fine the first time you run Synapse (after upgrading), but then when you restart the wrong value is pulled from `stream_positions`. 

... to avoid clashes with other SSO mechanisms

If a remote server name is provided, ensure it is something reasonable
before making remote connections to it.

Replace 'perspectives' config block with 'trusted_key_servers' in docker homeserver.yaml template (#9157)

Make sure we report the correct config path for errors in the OIDC configs.

...instead of just creating the exception object and doing nothing with it.

* Factor out a common TestHtmlParser

Looks like I'm doing this in a few different places.

* Improve OIDC login test

Complete the OIDC login flow, rather than giving up halfway through.

* Ensure that OIDC login works with multiple OIDC providers

* Fix bugs in handling clientRedirectUrl

 - don't drop duplicate query-params, or params with no value
 - allow utf-8 in query-params

setuptools 51.0.0 dropped support for Python 3.5.

0dd2649c (#9112) changed the signature of `auth_via_oidc`. Meanwhile,
26d10331 (#9091) introduced a new test which relied on the old signature of
`auth_via_oidc`. The two branches were never tested together until they landed
in develop.

We do this by allowing a single iteration to process multiple rooms at a
time, as there are often a lot of really tiny rooms, which can massively
slow things down.

I don't think there's any need to use canonicaljson here.

Fixes: #4475.

This is the final step for supporting multiple OIDC providers concurrently.

First of all, we reorganise the config so that you can specify a list of OIDC providers, instead of a single one. Before:

    oidc_config:
       enabled: true
       issuer: "https://oidc_provider"
       # etc

After:

    oidc_providers:
     - idp_id: prov1
       issuer: "https://oidc_provider"

     - idp_id: prov2
       issuer: "https://another_oidc_provider"

The old format is still grandfathered in.

With that done, it's then simply a matter of having OidcHandler instantiate a new OidcProvider for each configured provider.

Protecting media stops it from being quarantined when
e.g. all media in a room is quarantined. This is useful
for sticker packs and other media that is uploaded by
server administrators, but used by many people.

Previously this code generated unreferenced `Deferred` instances
which caused "Unhandled Deferreds" errors to appear in error
situations.

`distutils` is pretty much deprecated these days, and replaced with
`setuptools`. It's also annoying because it's you can't `pip install` it, and
it's hard to figure out which debian package we should depend on to make sure
it's there.

Since we only use it for a tiny function anyway, let's just vendor said
function into our codebase.