Fix Mastodon link rendering

man.sr.ht tries to be smart and generates mailto
for anything that looks like an email address.
Update location in the Fediverse
Elaborate on contributors' communication
Detail declaration instruction
Rework contrib guide and instruct on repo deriving
Add contributing instruction
Fix link for documentation source
Add a guide for users and mirror owners
Document checks' criteria
Fix typos and clarify README
Document publish process and locations on the Internet
Document declaration format
Draft goals and reasons
Use YAML for title
Initialize the docs