Add build-logic to make adding new modules easier

[vlsi]

Summary

This moves sigstore-java sources to sigstore-java folder. The move itself is done in a separate commit to make review easier.

Release Note

• Added build-logic to make adding new modules easier

Documentation

WDYT?

[vlsi]

Sorry for force-push storm. I just realized that I should move /build.gradle.kts -> /sigstore-java/build.gradle.kts before adding build logic.
Then Git realizes that /build.gradle.kts with added build logic is a brand new file, and it shows a better history for /sigstore-java/build.gradle.kts

[vlsi]

There's a recent idea to use /gradle/plugins folder instead of /build-logic: gradle/gradle#21192

[loosebazooka]

I'm having a hard time following this, sorry to ask you to break this up again. I think what would make this easier for is to just create the new dir structure without build logic updates.
/sigstore-java/sigstore-java.

The build-logic seem to apply pretty strongly to a gradle plugin? But maybe I'm misunderstanding it.

We could do build logic updates in a new PR.

[loosebazooka]

lgtm, just a few comments.

[vlsi]

I think what would make this easier for is to just create the new dir structure without build logic updates.
The build-logic seem to apply pretty strongly to a gradle plugin? But maybe I'm misunderstanding it.

I must have missed this.

I believe this PR adds only the bits that are required to build sigstore-java, and the build logic updates for building Gradle plugin are not here (they go in the last commit of #98)

[loosebazooka]

If this is ready to go, I'll merge it?

[vlsi]

Go ahead