Build Improvements

[asafflesch]

This PR fixes a pair of issues that prevent complete cacheability of certain tasks in the project's build:

1. All proto tasks rely on the root build.gradle file in such a way that the dependency is registered with the full absolute path of the project on the local node. This makes it impossible to cache those tasks between two nodes with a different directory layout. Fixed by specifying that the file path should be relative to the project dir.
2. The NettyResourceTransformer object in netty/shaded/build.gradle is not explicitly marked as cacheable. This, I admit, I took more of a guess that it was an oversight, but if there's a reason, I can drop that from the PR.

UPDATE:

These are the build scans that demonstrate the change:

1. Build scan from master
2. Build scan from PR

You can clearly see here that tasks move "not cacheable" to "cacheable" as a result of this change.

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: Faqa / name: Asaf Flescher (93be0a3, 3025d85, 7649cfb)

[runningcode]

looks good. just one suggestion. we should give the property a name so that it is easier to see and track.

[ejona86]

Yeah, we don't care about cachability in our build at all. I don't trust the feature enough to use it for the CI, which is where it'd do us the most good.