ci: reorganize SQUAD groups and projects

Reorganize SQUAD groups and projects to make it easier to find out what
is tested by looking at the group/project overview.

New group/project org.

```
squad/
├── merge-request
│   ├── meta-zephyr
│   └── oniro
├── release
├── scheduled-daily
│   ├── kselftest
│   ├── ltp
│   ├── perf
│   └── zephyr
└── scheduled-weekly
    └── gcc
```

This closes: #731

Signed-off-by: Chase Qi <chase.qi@linaro.org>