[Umbrella] Workload Scheduling

This is the full list of feature issues and PRs related to workload scheduling and the scheduling subsystem.

## Scheduling infrastructure and common tasks

- [X] https://github.com/ClickHouse/ClickHouse/pull/49671
- [X] https://github.com/ClickHouse/ClickHouse/pull/59013
- [X] https://github.com/ClickHouse/ClickHouse/pull/62165
- [X] https://github.com/ClickHouse/ClickHouse/pull/64061
- [X] https://github.com/ClickHouse/ClickHouse/pull/64985
- [X] https://github.com/ClickHouse/ClickHouse/pull/65654
- [X] https://github.com/ClickHouse/ClickHouse/pull/69187
- [X] https://github.com/ClickHouse/ClickHouse/pull/75999
- [ ] https://github.com/ClickHouse/ClickHouse/pull/108431
- [x] https://github.com/ClickHouse/ClickHouse/issues/79542
- [ ] https://github.com/ClickHouse/ClickHouse/issues/84623
- [ ] https://github.com/ClickHouse/ClickHouse/pull/116800

## IO scheduling

- [X] https://github.com/ClickHouse/ClickHouse/pull/41840
- [X] https://github.com/ClickHouse/ClickHouse/pull/45711
- [X] https://github.com/ClickHouse/ClickHouse/pull/54618
- [X] https://github.com/ClickHouse/ClickHouse/pull/59025
- [X] https://github.com/ClickHouse/ClickHouse/pull/65182
- [ ] https://github.com/ClickHouse/ClickHouse/issues/63212

## CPU and threads scheduling

- [X] https://github.com/ClickHouse/ClickHouse/pull/59032
- [X] https://github.com/ClickHouse/ClickHouse/pull/77595
- [X] https://github.com/ClickHouse/ClickHouse/pull/80879
- [ ] https://github.com/ClickHouse/ClickHouse/issues/84610
- [ ] https://github.com/ClickHouse/ClickHouse/issues/84965
- [ ] https://github.com/ClickHouse/ClickHouse/issues/93970
- [ ] https://github.com/ClickHouse/ClickHouse/issues/88304
- [ ] https://github.com/ClickHouse/ClickHouse/pull/117711
- [ ] https://github.com/ClickHouse/ClickHouse/issues/110581

## Query slot scheduling

- [X] https://github.com/ClickHouse/ClickHouse/pull/78415
- [X] https://github.com/ClickHouse/ClickHouse/pull/81250
- [ ] https://github.com/ClickHouse/ClickHouse/issues/84983

## RAM/Disk space reservations

- [ ] https://github.com/ClickHouse/ClickHouse/issues/109064
- [x] https://github.com/ClickHouse/ClickHouse/pull/82414
- [ ] https://github.com/ClickHouse/ClickHouse/issues/110876