feat: expose get flow factory

[aeneasr]

The getFlowFactory allows developers of the @ory/nextjs package to define their own get login, registration, verification, recovery, and settings fetch logic, while keeping all of the error handling and state transition logic intact.

Most people should use getLoginFlow and other variants instead.

[codecov]

Codecov Report

Attention: Patch coverage is 74.24242% with 17 lines in your changes missing coverage. Please review.

Project coverage is 42.63%. Comparing base (f3fad4d) to head (1cd64c8).
Report is 14 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #333      +/-   ##
==========================================
+ Coverage   42.43%   42.63%   +0.20%     
==========================================
  Files         136      138       +2     
  Lines        2008     2078      +70     
  Branches      288      307      +19     
==========================================
+ Hits          852      886      +34     
- Misses       1149     1181      +32     
- Partials        7       11       +4     

Components	Coverage Δ
@ory/elements-react	37.44% <40.47%> (+0.65%)	⬆️
@ory/nextjs	64.33% <74.24%> (-1.65%)	⬇️