Move code to generate apub urls into lemmy_api_common

crates/api_common/src/lib.rs

crates/api_crud/src/comment/create.rs

crates/api_crud/src/community/create.rs

crates/api_crud/src/post/create.rs

crates/api_crud/src/private_message/create.rs

crates/api_crud/src/site/create.rs

crates/api_crud/src/user/create.rs

crates/apub/src/activities/community/add_mod.rs

crates/apub/src/activities/community/remove_mod.rs

crates/apub/src/activities/mod.rs

crates/apub/src/collections/community_moderators.rs

crates/apub/src/collections/community_outbox.rs

crates/apub/src/http/community.rs

crates/apub/src/http/person.rs

crates/apub/src/lib.rs

crates/apub/src/objects/community.rs

crates/apub/src/objects/person.rs

crates/apub/src/protocol/collections/group_followers.rs

src/code_migrations.rs