add singleton resource manager
remove unused classes
add certificate manager
update cert manager interface, partial implementation
implement GenerateRootCA
totally implement cert manager
add interface
fix crash issue: cert manager is not constructed
add certificate request verification logic
fix issue: root ca with serial number other than 0 will not be accepted by browsers
add interface, and update data structure, to avoid CA copy
init cert manager at the start
update direct handler using cert manager
fix crash issue: init root_ca_ before using it
little change: refine logic
fix compilation error using GCC
update proxy handler using cert manager
update format
add dh parameters loading, generation, saving
remove unused root ca ssl context and unused headers