refactor!: new aztec command (#17792)

The title of the PR is vague because there is a lot of changes in this
PR.

Other than tackling these issues here:

Closes
https://linear.app/aztec-labs/issue/F-41/replace-aztec-nargo-init-with-aztec-init
Closes
https://linear.app/aztec-labs/issue/F-43/replace-aztec-nargo-compile-with-aztec-compile
Closes
https://linear.app/aztec-labs/issue/F-44/aztec-compile-help-will-override-the-nargo-compile-help-with-aztec
Closes
https://linear.app/aztec-labs/issue/F-48/add-aztec-check-and-aztec-fmt

I also:
- Added `aztec new` command that is like `aztec init` but instead calls
`nargo new`. This was necessary as we used `aztec-nargo new` in docs
etc. Hence I needed the `aztec new counterpart`.
- I dropped the `aztec-postprocess-contract` directory containing the
`transpile_contract_and_gen_vks.sh` script because it now only called
the aztec_process command in bb which made this basically a tech debt
from time where we forced devs to call this script manually.
- Went to occurrences of "aztec-nargo" and "aztec-postprocess-contract"
strings in the codebase and docs and did the relevant updates.
- I replace the default contract template that `nargo init --contract`
and `nargo new --contract` commands spit out with:

```
use aztec::macros::aztec;

#[aztec]
contract Main {}
```

This results in the `aztec-nargo` and `aztec-postprocess-contract` being
deprecated (and deleted).

Thought it's fine to do all these changes in one PR because the
complexity of the changes is low.

Author: benesjan

aztec-postprocess-contract/README.md

@@ -9,13 +9,9 @@ That is all.
 This will install into `~/.aztec/bin` a collection of scripts to help with running aztec containers, and will update
 the user's `PATH` variable in their shell startup script so they can be found.
 
-- `aztec` - The infrastructure container.
-- `aztec-cli` - A command-line tool for interacting with infrastructure.
-- `aztec-nargo` - A build of `nargo` from `noir` that is guaranteed to be version-aligned. Provides compiler, lsp and more.
-- `aztec-postprocess-contract` - Postprocessing tool for Aztec contracts that transpiles artifacts using `avm-transpiler` and generates verification keys using `bb`.
-- `aztec-sandbox` - A wrapper around docker-compose that launches services needed for sandbox testing.
-- `aztec-up` - A tool to upgrade the aztec toolchain to the latest, or specific versions.
-- `aztec-builder` - A useful tool for projects to generate ABIs and update their dependencies.
+- `aztec` - a collection of tools to compile and test contracts, to launch subsystems and interact with the aztec network."
+- `aztec-up` - a tool to upgrade the aztec toolchain to the latest, or specific versions."
+- `aztec-wallet` - our minimalistic CLI wallet"
 
 After installed, you can use `aztec-up` to upgrade or install specific versions.