## Description
Internalize some libs. This reduces the amount ot public API tendermint is supporting. The moved libraries are mainly ones that are used within Tendermint-core.
## Description
This PR wraps the stdlib sync.(RW)Mutex & godeadlock.(RW)Mutex. This enables using go-deadlock via a build flag instead of using sed to replace sync with godeadlock in all files
Closes: #3242
* libs/common: refactor libs common 3
- move nil.go into types folder and make private
- move service & baseservice out of common into service pkg
ref #4147
Signed-off-by: Marko Baricevic <marbar3778@yahoo.com>
* add changelog entry
* [libs/events] add more godoc comments
* [libs/events] refactor code
- improve var naming
- improve code structure
- do not use defers for unlocking mutexes (defer takes time)
