- Turned them all into functions to also do asserts etc.
- The llist related structs got all their fields renamed in order to make
sure no existing code remains using direct access.
- Each list node struct now points back to the list it "lives in", so
Curl_node_remove() no longer needs the list pointer.
- Rename the node struct and some of the access functions.
- Added lots of ASSERTs to verify API being used correctly
- Fix some cases of API misuse
Add docs/LLIST.md documenting the internal linked list API.
Closes#14485
