The declarations that are printed by the kotlinp tool may be optionally
sorted. That's controlled by `sortDeclarations` flag in
`org.jetbrains.kotlin.kotlinp.Settings`. However, there was no sorting
implemented for `KmClass`es.
This commit fixes that.
^KT-62340
This commit includes:
1. New subproject :tools:kotlinp-klib that contains the facade for
rendering the metadata in "kotlinp" format given just
KlibModuleMetadata
2. A tool for computing (external) IR signatures that are not directly
available in metadata: KlibKotlinpExternalSignatureComputer
^KT-62340