Fixes and improvements to meshtastic.rs generation

[krant]

• Make generated meshtastic.rs the same for ts-gen and serde features. Fixes Building with --features ts-gen corrupts future builds without it #53.
• Apply clippy directives to whole generated file meshtastric.rs instead of per-struct approach.

[brannondorsey]

Thanks for the fix @krant. I can confirm that this fixes the issue, and successive builds with --features ts-config, --features serde, and the default features all succeed and leave the project compilable afterwords without issue.

I left one small nonblocking comment.

[brannondorsey]

Would we want to take a similar approach for the #[serde(rename_all = \"camelCase\")] attribute just below here as well?

Also, I think the two #[allow(clippy::*)] attributes may be something that can be added independent of whether the serde feature is enabled or not. That's at least what my understanding was here in this PR last week: #52 (comment)

[krant]

That's a nice improvement, thanks @brannondorsey. build.rs looks way better now.

[lukipuki]

Please fix the conflict and then I can merge

[krant]

@lukipuki rebased on top of main