When I folded the Analytics modules I used a procedure suggested by Joe, here an example:

https://gerrit.wikimedia.org/r/#/c/520267/
https://gerrit.wikimedia.org/r/#/c/520271/

The above procedure assumes that git history is not worth folding in, very important point :)

As follow up, the module should also be archived like T227164

Change 547500 had a related patch set uploaded (by Jbond; owner: John Bond):
[operations/puppet@production] Move the nginx submodule into the repository - part 1

https://gerrit.wikimedia.org/r/547500

Change 547501 had a related patch set uploaded (by Jbond; owner: John Bond):
[operations/puppet@production] Move the zookeeper zabbix into the repository - part 2

https://gerrit.wikimedia.org/r/547501

Change 521323 had a related patch set uploaded (by BBlack; owner: BBlack):
[operations/puppet@production] Un-submodule for nginx: move to prod env [1/2]

https://gerrit.wikimedia.org/r/521323

Change 521324 had a related patch set uploaded (by BBlack; owner: BBlack):
[operations/puppet@production] Un-submodule for nginx: rename to orig path [2/2]

https://gerrit.wikimedia.org/r/521324

Change 521324 merged by BBlack:
[operations/puppet@production] Un-submodule for nginx: rename to orig path [2/2]

https://gerrit.wikimedia.org/r/521324

Change 547536 had a related patch set uploaded (by BBlack; owner: BBlack):
[operations/puppet/nginx@master] Final commit, deprecate old nginx submodule repo

https://gerrit.wikimedia.org/r/547536

Change 547501 abandoned by Jbond:
Move the zabbix into the repository - part 2

Reason:
no longer required

https://gerrit.wikimedia.org/r/547501

Change 547500 abandoned by Jbond:
Move the nginx submodule into the repository - part 1

Reason:
no longer required

https://gerrit.wikimedia.org/r/547500

Change 547539 had a related patch set uploaded (by BBlack; owner: BBlack):
[integration/config@master] Archive the puppet nginx submodule

https://gerrit.wikimedia.org/r/547539

Change 547540 had a related patch set uploaded (by BBlack; owner: BBlack):
[integration/config@master] puppet integration: un-submodule cleanup

https://gerrit.wikimedia.org/r/547540

Change 547536 merged by BBlack:
[operations/puppet/nginx@master] Final commit, deprecate old nginx submodule repo

https://gerrit.wikimedia.org/r/547536

Change 547539 merged by jenkins-bot:
[integration/config@master] Archive the puppet nginx submodule

https://gerrit.wikimedia.org/r/547539

Change 547540 merged by jenkins-bot:
[integration/config@master] [puppet] Complete the un-submodule cleanup

https://gerrit.wikimedia.org/r/547540

Mentioned in SAL (#wikimedia-releng) [2019-10-31T16:25:56Z] <James_F> Zuul: [puppet] Complete the un-submodule cleanup T230206

[batch] remove patch for review tag from resolved tasks