Add proper `commit_all` to `TestExternalities` (#7808)

* Add proper `commit_all` to `TestExternalities`

This pr adds a propoer `commit_all` function to `TestExternalities` to
commit all changes from the overlay to the internal backend. Besides
that it fixes some bugs with handling empty dbs when calculating a delta
storage root. It also changes the way data is added to the in memory
backend.

* Update primitives/state-machine/src/testing.rs

Co-authored-by: cheme <[email protected]>

* Don't allow self proxies (#7803)

* Allow council to slash treasury tip (#7753)

* wk2051 | D4 |Allow council to slash treasury tip | p1

* Update frame/tips/src/lib.rs

Co-authored-by: Xiliang Chen <[email protected]>

* wk2051 | D5 |Allow council to slash treasury tip | p2

* wk2051 | D5 |Allow council to slash treasury tip | p3

* wk2051 | D5 |Allow council to slash treasury tip | p4

* wk2051 | D5 |Allow council to slash treasury tip | p5

* random change

* cargo run --release --features=runtime-benchmarks --manifest-path=bin/node/cli/Cargo.toml -- benchmark --chain=dev --steps=50 --repeat=20 --pallet=pallet_tips --extrinsic=* --execution=wasm --wasm-execution=compiled --heap-pages=4096 --output=./frame/tips/src/weights.rs --template=./.maintain/frame-weight-template.hbs

* fix typo

* Update frame/tips/src/lib.rs

Co-authored-by: Kian Paimani <[email protected]>

* Update frame/tips/src/lib.rs

Co-authored-by: Kian Paimani <[email protected]>

* Update frame/tips/src/lib.rs

Co-authored-by: Kian Paimani <[email protected]>

* Update frame/tips/src/lib.rs

Co-authored-by: Kian Paimani <[email protected]>

* Update frame/tips/src/tests.rs

Co-authored-by: Kian Paimani <[email protected]>

* wk2052 | D1 | Allow council to slash treasury tip | p6

Co-authored-by: Xiliang Chen <[email protected]>
Co-authored-by: Shawn Tabrizi <[email protected]>
Co-authored-by: Parity Benchmarking Bot <[email protected]>
Co-authored-by: Kian Paimani <[email protected]>

* Review feedback

* Review feedback

* Update docs

* More docs

* Make it private

* Use `None`

* Use apply transaction

* Update primitives/state-machine/src/testing.rs

Co-authored-by: cheme <[email protected]>
Co-authored-by: Shawn Tabrizi <[email protected]>
Co-authored-by: RK <[email protected]>
Co-authored-by: Xiliang Chen <[email protected]>
Co-authored-by: Parity Benchmarking Bot <[email protected]>
Co-authored-by: Kian Paimani <[email protected]>
Co-authored-by: Guillaume Thiolliere <[email protected]>