Log the project's git commit and lightning-kmp version

[dpad85]

The goal of this PR is to be able to track exactly what commit and what version of lightning-kmp Phoenix is using at a given time, to help with debugging. These informations are printed in the logs, when the NodeParamsManager starts.

To do this in Eclair, we put the git-commit in eclair-core manifest.

The solution here is similar: in the gradle build file of phoenix-shared, we added a new task buildVersionsTask that generates a file in phoenix-shared/build/generated-src/<package>:

object BuildVersions {
    const val PHOENIX_COMMIT = "735a8bcfbbc64b0fb08d27ba46449c0b9aef3e91"
    const val LIGHTNING_KMP_VERSION = "1.5.6"
}

This task is started every time the sources are compiled (and its output is marked as a source directory for Android Studio) with:

kotlin.srcDir(task.map { it.destinationDir })`

We could use the same technique in lightning-kmp (and all our other kmp libraries like bitcoin-kmp).

[dpad85]

@t-bast let me know what you think about this, and if we should do the same for lightning-kmp, bitcoin-kmp, secp256k1-kmp.