Fix 3rd-party cog repo branch and maintainership changes

[synrg]

There are some 3rd-party cog repo branch and maintainership changes recently that require action on our part in order to continue using supported versions of those cogs:

• Laggron announced today (Oct 30, 2023) on his channel on the cog support discord that he has finally merged his dpy-2.0 branch to the default v3 branch.
• For us, this means the say cog (installed on several bots) needs to change, e.g.

,repo add Laggrons-Dumb-Cogs https://github.com/laggron42/Laggrons-Dumb-Cogs
,cog uninstall say
,cog install Laggrons-Dumb-Cogs say
,load say

After confirming there are no further cogs installed from the old repo (i.e. nothing listed as "installed" from the 1st command below), delete it:

,cog list Laggron-Dumb-Cogs-dpy2
,repo delete Laggrons-Dumb-Cogs-dpy2

• Repeat this per bot that uses the old branch.

Additionally, phen announced weeks ago that he is giving up most, if not all of his cogs to other maintainers. The ones we use have new maintainers except for simplecalculator. So similar steps need to be taken for his cogs, except instead of just changing branches, there's a repo change for each.

• Seina-cogs has taken over tags and roleutils:
  • https://github.com/japandotorg/Seina-Cogs
• AAA3A-cogs has taken over embedutils
  • https://github.com/AAA3A-AAA3A/AAA3A-cogs
  • Polistes already has this repo added for seen cog, so only the other bots using this cog need to have it added.
• AAA3A-cogs has his own calculator cog that will do as a replacement for phen's simplecalculator
  • It's an entirely new cog, not a port, so although the -calc command for Dumbo is the same, the differences should be noted and announced. We have some pins around our channels and also something in our docs about it, so those should be updated as well.

Finally, update the backup bot instances and README.md, completing the switchover.