Axon 201 implement experiment flow split

[cabella-dot]

Loom: https://www.loom.com/share/19e0e4b8bfc347d58404b0bb4c75cfa3

Due to the nature of this experiment (only first time installers will be put into cohorts):

• changed experiment fetching to be outside of initialization
• implemented exp flow in extension.ts

Now, only users whose previousVersion === undefined will be placed into exp cohorts:

• A - control
• B - jump to settings page auth
• C - jump to legacy auth flow
• D - jump to new auth flow

[sdzh-atlassian]

Left a couple small questions