Explore a way to replace hook_page_bottom() with hook_page_attachments()

Problem/Motivation

Core allows to control order of loaded files but the module using hook_page_bottom() to attach assets.
So modules like advagg can't deal with the module's assets

Proposed resolution

Looking at google ananytics code it using hook_page_attachments() so probably hook could be changed

Remaining tasks

- research replacement and figure out effect in page speed/lighthouse
- patch with fix or document why the current hook is used

User interface changes

no

API changes

no

Data model changes

no