Post-release cleanup and fixes (specific to recent repository restructure) (googleapis#3290)

1) Fix poms deployment config.
2) Fix documentaiton links in readmes.
3) Update main README (remove `goolge-cloud` metapackage reference).
4) Update `RELEASING.md` to reflect changes. The instructions try to avoid having mysterious scripts running in the release process and also ensures that all disruptive operations (actual release/push) are done explicitly and not somewhere in the middle of a mysterious script.
5) Remove `deploy.sh` and `finalize_release.sh` scripts.
6) Fix few previously broken links (bigquerydatatransfer and compute apidocs links)

Author: vam-google

java-bigtable/google-cloud-bigtable/README.md

@@ -171,4 +171,4 @@ Apache 2.0 - See [LICENSE] for more information.
 [cloud-platform]: https://cloud.google.com/
 [cloud-bigtable]: https://cloud.google.com/bigtable/
 [bigtable-product-docs]: https://cloud.google.com/bigtable/docs/
-[bigtable-client-lib-docs]: https://googlecloudplatform.github.io/google-cloud-java/latest/apidocs/index.html?com/google/cloud/bigtable/package-summary.html
+[bigtable-client-lib-docs]: https://googlecloudplatform.github.io/google-cloud-java/google-cloud-clients/apidocs/index.html?com/google/cloud/bigtable/package-summary.html