Similarly to #15856, moves lib/ protos (except for Connect) under the proto/ tree.
The intended layout is a mirror of api:
```
teleport-root
proto/ <- root for protos and proto imports
teleport/
lib/...
gen/proto/go/ <- ideal root for generated protos
```
#15187
* Move lib/ protos under the proto/ tree
* Reformat protos
* Update generated protos