Placement of Classroom practices list

### How could the content be improved?

At some level, by the time we get to the list in episode 21 (working with your team) we have been referring to/implying these practices for 3/4 of the training by this point prior to explicitly introducing them as a list here. This section is also a lot of text without an exercise.

I propose
1. move the explicit definition of each of the practices to the first time they are referenced
2. Add to the [overview](https://github.com/carpentries/instructor-training/blob/main/episodes/01-welcome.md?plain=1#L185) section that we will be introducing a number of explicit classroom practices and how to work with them throughout the training
3. put an exercise in this episode where trainees either as a whole class group or in small groups try to produce the list of practices or take turns describing them to one another or maybe connecting them to the why (since most are actually introduced in conjunction with the why)?

If we do this, I think the practices would be introduced at:
- Starting with the Code of Conduct: 09-eia ?
- Participatory Instruction \& Hands-off Help: 17-live/ [02-practice-learning](https://github.com/carpentries/instructor-training/blob/main/episodes/02-practice-learning.md?plain=1#L31) and [08-motivation](https://github.com/carpentries/instructor-training/blob/main/episodes/08-motivation.md?plain=1#L262-L265)
- Sticky notes: [01-welcome](https://github.com/carpentries/instructor-training/blob/main/episodes/01-welcome.md?plain=1#L169) and [02-practice-learning](https://github.com/carpentries/instructor-training/blob/main/episodes/02-practice-learning.md?plain=1#L45-L49)
- formative assessment: [05-memory](https://github.com/carpentries/instructor-training/blob/main/episodes/05-memory.md?plain=1#L272)
- breaks: 02-memory ?
- feedback: [06-feedback](https://github.com/carpentries/instructor-training/blob/main/episodes/06-feedback.md)

### Which part of the content does your suggestion apply to?

https://github.com/carpentries/instructor-training/blob/main/episodes/21-management.md?plain=1#L106

Start with episodes/21-management.md around the classroom practices list, then review the referenced sections in episodes/01-welcome.md, 02-practice-learning.md, 05-memory.md, 06-feedback.md, 08-motivation.md, 09-eia, and 17-live. Done means the practices are introduced at their earlier references, the overview signals them, and episode 21 includes an exercise for reviewing them.

Written by the indexing model from the issue text.