fixes before release v10.1.0

Description

Should fix #401

[ ] dynamic tables: give the focus to first input when adding a row
[ ] fix npm run lint so it can handle lit linting errors
[ ] fix lit linting errors
[ ] dynamic table: add titles to "+" and "-" buttons
[ ] dynamic table: add confirmation when deleting a line
[ ] channel configuration: add a cancel button that reload data from backend
[ ] channel emojis: add a cancel button
[x] in channel-detail, channel-configuration, ... there are some public attributes prefixed by _, and some private attributes without the prefix. Clean that.
[ ] _asyncTaskRender: handle error (and pending?) case (this method exists in several elements)
[ ] check that there is no missing localization for error messages (no hard coded labels)
[ ] dynamic tables: column description on thead title attribute is not very accessible (does not work on mobile, is not easy to find if user don't know it exists)
[ ] channel configuration: table too large?

[ ] I have added a description of the changes in the CHANGELOG files
[ ] I have run npm run lint to check that my changes respects the coding conventions
[ ] I have added user documentation for the new features I added
[ ] I have added technical documentation for the new features I added
[ ] I added some documentation and I have run npm run doc:translate to generate translations files