Adapt whole plugin codebase to 3.0 release API use

- Adapt to the replacement of RefConfigSection with AccessSection.
- Adapt to the InvalidNameException package move.
- Adapt to using a ProjectConfig.Factory for project config reading.
- Adapt to replacing member with getter in ProjectCreationValidatorIT.

Bug: Issue 11116
Change-Id: I09a3d6a12ff5c1b527bd91547c357ad46bade582
3 files changed