Fix deface overrides for zeitwerk reload

[sanak]

Fix farend/redmine_message_customize#67

Changes proposed in this pull request:

• Better deface override definition (override each method level) from referring the following file.
  • https://github.com/nanego/redmine_customize_core_fields/blob/master/app/overrides/issues/new.rb
  • https://github.com/jbbarth/redmine_base_deface/blob/master/init.rb#L13-L39
• Similar with Fix Zeitwerk reload issue redmine_custom_fields_groups#38
• Includes PR:Limit ol-ext version to 4.0.18 and update yarn.lock #331 temporarily to avoid CI error.

@gtt-project/maintainer

[sanak]

Thanks!
I will merge this by rebase with dropping 1st commit which is same as PR:#331.

[sanak]

I will merge this by rebase with dropping 1st commit which is same as PR:#331.

Well, git rebase -i next doesn't show 1st commit, so I merge this as it is.