CHT-Api library should change behavior to adapt to differing cht-core version

[kennsippell]

#114

• Look up the cht-core version during login and attach version information to the session. This requires all users to be logged out on deployment.
• This change updates ChtApi with two new versions ChtApi_4_6 which adapts to handles cht-core#8674 or ChtApi_4_7 which handles cht-core#8877
• ChtApi is now created via factory pattern ChtApi.create()
• I have elected not to use cht-core#8986 for reasons details here. It is just an awkward place to create variant-aware logic because it is pre-login.
• I removed the chtSession from the FastifyRequest object and replaced it with a ChtApi object. This was originally required to avoid a circular dependency but is no longer required. I kinda liked it a bit more so left it in the changes.