Consider enabling more aggressive optimizations for the Dist profile: Fat LTO and codegen-units = 1 #9

Hi!

I see that the project already uses ThinLTO in the Dist profile in the root Cargo.toml file. However, ThinLTO is usually less efficient from the perspective of performed optimizations than Fat (aka Full) LTO, and cargo-dist/dist defaults are not the most optimal by default. Additionally, I suggest enabling codegen-units = 1 (CU1) too. Enabling more advanced optimizations allows us to reduce the binary size further (always a good thing) and can improve the application performance a bit more. Especially since these flags are already a part of the rmk-template :)

Basically, it can be enabled with the following change:

[profile.dist]
inherits = "release"
codegen-units = 1
lto = true

I have made quick local tests (AMD Ryzen 9 5900x, Fedora 43, Rust 1.94, the latest version of this project at the moment, cargo build --profile dist command, no stripping) - the results are below.

• ThinLTO (current Dist profile): 11 Mib, clean build time: 19s
• ThinLTO + CU1: 9.0 Mib, clean build time: 43s
• FatLTO: 8.7 Mib, clean build time: 53s
• FatLTO + CU1: 8.1 Mib, clean build time: 1m 04s

Since the Dist profile is used only for release binaries, this build time increase shouldn't be a problem for the project. In exchange to build time, we will deliver a more optimized binary to users by default. Build time is also shouldn't be a problem for users who already uses recommended by the project cargo binstall since it just downloads binary from GitHub Releases (btw thank you for providing the prebuilt binaries!).

We can also apply the optimized Cargo settings to the Release profile, so cargo install will also deliver by default smaller binaries. But it's another topic for discussion - it doesn't block the Dist profile optimization proposal above. However, it would be nice to do it in one PR (ofc if you agree with the proposal).

Thank you.