[RTE-608] Remove mopa crate from the cargo

[gilanghamidy]

mopa is used only in sgx-detect tool, as a legacy workaround on generic programming with polymorphic types. Newer Rust now supports type upcasting, allowing std::any::Any to be used instead of using mopa::Any.

This should fix the Dependabot alert related to mopa crate:

• https://github.com/fortanix/rust-sgx/security/dependabot/5
• https://github.com/fortanix/rust-sgx/security/dependabot/40

Credit fo solution: @tvsfx

Verified the tools are working on the SGX machine.

[Taowyoo]

Nit:
You need to bump version if need to publish new version.
(This could be done in separate PR.)

[gilanghamidy]

I just update it now so to not make a separate PR. Thanks for noting this. :)

[tvsfx]

Nit: I forgot to add this, but when adding modern compiler features, it might be worthwhile setting the rust-version key (documentation), in this case presumably to 1.86 (cargo msrv can tell you). This information is actually used properly by the resolver nowadays and gives warnings when trying to cargo add/ cargo install a crate.

For example, if I try to install a crate that has a higher MSRV than my selected toolchain, I get:

cargo install --path .                                                                                 ✔ 
  Installing msrv-test v0.0.0 (/home/thomas/rust-toy)
error: failed to compile `msrv-test v0.0.0 (/home/thomas/rust-toy)`, intermediate artifacts can be found at `/home/thomas/rust-toy/target
`.
To reuse those artifacts with a future compilation, set the environment variable `CARGO_TARGET_DIR` to that path.

Caused by:
  rustc 1.80.0-nightly is not supported by the following package:
    msrv-test@0.0.0 requires rustc 1.86