[BITCOIN-ABC][WEB] Allowing rust analyser to work in web/explorer

Summary:
This error appears in the output section on VScode:

2024-12-05T03:00:51.754466Z ERROR notification handler failed handler=textDocument/didSave error=file not found: /Users/hazza/bitcoin-abc/web/explorer/explorer-exe/Cargo.toml

Removed the Cargo.toml + Cargo.lock file in explorer and appended the 'Cargo.toml paths for explorer-exe && explorer-server into the main workspace in bitcoin-abc/Cargo.toml

This allowed rust analyzer to work on .rs files inside the explorer dir.

Test Plan: ninja check-functional cargo check cargo run

Reviewers: tobias_ruck, #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Subscribers: Fabien

Differential Revision: https://reviews.bitcoinabc.org/D17292