In this PR:
- Separate projects to three modules: common, library_generation and
release_note_generation
- Add `generate_release_note.py` to separate PR description generation
from `entrypoint.py`.
- Only install common and library_generation module in image.
- Remove PR description comparison in integration test.

Example generation workflow in downstream library:
https://github.com/googleapis/java-bigtable/actions/runs/11442581326/job/31833887512

Note that `release_note_generation` module still depends on
`library_generation` module because we didn't separate config change
functions into `common` module. This will be in a follow up PR.

🤖 I have created a release *beep* *boop*
---


<details><summary>2.48.1-SNAPSHOT</summary>

### Updating meta-information for bleeding-edge SNAPSHOT release.
</details>

---
This PR was generated with [Release
Please](https://github.com/googleapis/release-please). See
[documentation](https://github.com/googleapis/release-please#release-please).

Co-authored-by: release-please[bot] <55107282+release-please[bot]@users.noreply.github.com>

chore: update googleapis commit at Wed Oct 23 02:26:27 UTC 2024

---------

Co-authored-by: Min Zhu <[email protected]>

…ifest file to get version (#3315)

#3314 3314

chore: update googleapis commit at Fri Oct 25 02:27:09 UTC 2024

… to v2.35.1 (#3316)

[error-prone
v2.35.1](https://github.com/google/error-prone/releases/tag/v2.35.1)
includes protobuf-java downgrade that is needed by customers.

🤖 I have created a release *beep* *boop*
---


<details><summary>2.49.0</summary>

##
[2.49.0](v2.48.0...v2.49.0)
(2024-10-25)


### Features

* Move release note generation to a sub module
([#3299](#3299))
([7d6d66a](7d6d66a))


### Bug Fixes

* add additional potential exceptions when retrieving protobuf manifest
file to get version
([#3315](#3315))
([ef9e518](ef9e518))


### Dependencies

* update dependency com.google.errorprone:error_prone_annotations to
v2.35.1
([#3316](#3316))
([d7c290f](d7c290f))
</details>

---
This PR was generated with [Release
Please](https://github.com/googleapis/release-please). See
[documentation](https://github.com/googleapis/release-please#release-please).

Co-authored-by: release-please[bot] <55107282+release-please[bot]@users.noreply.github.com>