Bugfix/missing peerdeps

[a-gagnon]

~~Add missing peerDependencies that are required at runtime by the map-layers package. Besides type imports, anything that is used by the package should be a direct dependency, or be in both devDependency and peerDependency.~~

• Move some devDependencies to direct dependencies

Found the problem when adding the @itwin/map-layers package to my test-app. I didn't get a warning for missing peerDependency, but it complained about missing @itwin/map-layers-formats at build time.

[bsy-nicholasw]

@a-gagnon This is old and no one approved...does it need additional update before we can complete it?

[a-gagnon]

@a-gagnon This is old and no one approved...does it need additional update before we can complete it?

Haven't played with the app since then, but those should really be deps. I think it's fine to approve.