* Add matrix_bridges_msc4190_enabled flag for using msc4190 on supported mautrix bridges.
* Apply to_json to msc4190 in mautrix configs
* Add | to_json to mautrix bridge registration io.element.msc4190.
* require matrix_synapse_experimental_features_msc3202_device_masquerading_enabled for matrix_bridges_msc4190_enabled
* Also add msc4190 support for mautrix-telegram
* mautrix-meta: enable spaces; add a hint into the display name
* use the meta mode to determine displayname suffix
* Allow for people to easily unset the mautrix-meta displayname suffix
Previously, unsetting `matrix_mautrix_meta_messenger_bridge_displayname_suffix`
or (`matrix_mautrix_meta_instagram_bridge_displayname_suffix`) variable would
make you end up witha trailing space in `displayname`.
It's possible that mautrix-meta trims this, but I haven't checked. It's
better not to risk it anyway.
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Co-authored-by: Slavi Pantaleev <slavi@devture.com>
