fix: report a more specific error when plugin is dropped while we're waiting for enable plugin operation to finish

- Simplify code
- Check plugin exists on client side

- Move all preconditions checking to the client
- Return errors if preconditions fail instead of silently ignoring them

Dmitry Ivanov authored 7 months ago and Dmitry Rodionov committed 6 months ago

Build:

```
$ make build --dry-run
echo "" > tarantool-sys/VERSION
if test -f ~/.cargo/env; then . ~/.cargo/env; fi && \
	cargo build --locked  --features webui

$ make build --dry-run -j1
echo "" > tarantool-sys/VERSION
if test -f ~/.cargo/env; then . ~/.cargo/env; fi && \
	cargo build --locked -j1 --features webui
```

Test:

```
$ make test --dry-run
cargo test --locked
pipenv run pytest --numprocesses=auto

$ make test --dry-run
cargo test --locked -j1
pipenv run pytest  --numprocesses=1
```

Lint:

```
$ make lint --dry-run
cargo fmt --check
cargo check --locked
cargo clippy --version
cargo clippy \
	--locked  \
	--features=load_test,error_injection,webui \
	-- --deny clippy::all --no-deps
RUSTDOCFLAGS="-Dwarnings -Arustdoc::private_intra_doc_links" \
	cargo doc \
		--locked  \
		--workspace --no-deps --document-private-items \
		--exclude={tlua,sbroad-core,tarantool}
pipenv run lint

$ make lint --dry-run -j1
cargo fmt --check
cargo check --locked -j1
cargo clippy --version
cargo clippy \
	--locked -j1 \
	--features=load_test,error_injection,webui \
	-- --deny clippy::all --no-deps
RUSTDOCFLAGS="-Dwarnings -Arustdoc::private_intra_doc_links" \
	cargo doc \
		--locked -j1 \
		--workspace --no-deps --document-private-items \
		--exclude={tlua,sbroad-core,tarantool}
pipenv run lint
```

- Don't ignore operation if plugin is already enabled,
  the client must take care of this via the CaS ranges

- Don't propose mutliple Raft operations during one step as this may
  lead to inconsistencies in case of crashes

- Don't ignore operation if plugin is already installed,
  the client must take care of this via the CaS ranges

- Don't propose multiple Raft operations during one step as this may
  lead to inconsistencies in case of crashes