docs(core files): Fix links in CONTRIBUTING.md, CODE_OF_CONDUCT.md, and MAINTAINERS.md

[lwasser]

Fix links in

• CONTRIBUTING.md : for now I added a note that all of these links are broken!! But when docs(translations): META ISSUE for migration #903 is complete, we will be able to update all links in that file to the correct translation locations
• CODE_OF_CONDUCT.md, see docs(coc): Turn the code of conduct email into a form that a group of people will get #893 for the email contact associated with that file. But also it would be helpful for someone to read the COC closely and make sure it's still what we want / need for this project!!
• MAINTAINERS.md

We currently have several core files that haven't been updated in some time. We will want to go through each file, and make sure that links and content are current.

I just had a look at MAINTAINERS.md, and we probably will want to chat with the entire team to decide what to do with that file.

If anyone wants to begin to chip away at this, that would be great. This is a great community oriented task that someone could take on. It doesn't require significant technical expertise to help here!!

[lwasser]

We could also break this issue up into 3 if someone wants to take on one part of it!! That is probably the best path forward, and I'm happy to create new issues if people chime in here that they'd like to work on part of this.