Params refactor, simplified (#2300)

* always c++

* Create C++ params class

* get works

* tests hang now

* passes tests

* cleanup string formatting

* handle interrupt in blocking read

* fix memory leak

* remove unused constructor

* Use delete_db_value directly

* Rename put -> write_db_value

* filename cleanup

* no semicolons in cython

* Update common/SConscript

Co-authored-by: Adeeb Shihadeh <adeebshihadeh@gmail.com>

* add std::string version of delete_db_value

* This is handled

* cleanup encoding

* Add clear method to clear all

* add persistent params

* fix android build

* Should be called clear_all

* only import params when needed

* set params path on manager import

* recusrively create directories

* Fix function order

* cleanup mkdirp

Co-authored-by: Adeeb Shihadeh <adeebshihadeh@gmail.com>
Co-authored-by: Comma Device <device@comma.ai>
old-commit-hash: 2e182e5c574ea1468678b5fd8d0597e34ed5898d