Allow setting constants via manifest

[preston-evans98]

Description

This PR adds the #[config_constant] attribute, which sets a constant from the manifest file. This functionality will be used in several places, but is blocking for the soft-confirmations workflow (where we need to set the inbox_delay for forced transactions per-rollup instead of hard-coding it).

#[config_constant]
pub const TEST_ARRAY_OF_U8: [u8; 32];

fn main() {
 // The value is filled from `constants.json`, allowing this assertion to pass
 assert_eq!(TEST_ARRAY_OF_U8, [255;32])
}

This macro is exported from sov_modules_api::macros.

N.B.: This PR only implements basic types (numeric types, strings, booleans, and arrays). Support for more complex types is left unimplemented for now.

Testing

A new test has been added using trybuild to ensure that valid values are produced for the covered types.

Docs

A doc comment has been added

[codecov]

Codecov Report

Merging #1030 (2e90d22) into nightly (0890fd1) will decrease coverage by 0.1%.
The diff coverage is 64.9%.

Files	Coverage Δ
module-system/sov-modules-macros/src/lib.rs	100.0% <100.0%> (ø)
...le-system/sov-modules-macros/src/make_constants.rs	100.0% <100.0%> (ø)
module-system/sov-modules-macros/src/manifest.rs	64.0% <58.3%> (-0.1%)	⬇️

... and 2 files with indirect coverage changes

[vlopes11]

Looks good! It's a nice improvement to have tests over the functionality.

A couple of non-blocking comments & suggestions