`no_ui` output is used when a local UI must not be created, e.g.; because the stream is
piped out. The `--no-ui` option has been removed because using a dedicated output seems
like a better approach.
- file send/receive commands now supports webRTC transfer. In `send` command, the
`--webrtc` flags is currenty used to activate it.
- WebRTC related code have been factorized and moved to `libervia.frontends.tools.webrtc*`
modules.
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- Moved original UI to a separated class, and use if with the `simple` output
- By default, best output is automatically selected. For now `gui` is selected if possible,
and `simple` is used as fallback.
- The new `tui` output can be used to have the videos directly embedded in the terminal,
either with real videos for compatible terminal emulators, or with Unicode blocks.
- Text contrôls are used for both `simple` and `tui` outputs
- several options can be used with `--oo` (will be documented in next commit).
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