Add disable personal access tokens to ApplicationSettings

What does this MR do and why?

In !97299 (merged), we added the functionality to disable personal access tokens in FIPS mode. This change refactors it by introducing a new ApplicationSettings, independent of FIPS mode.

Related to #384201 (closed).

Migration output

up

$ rake db:migrate:up:main VERSION=20221205061134                                                                                                                        
main: == 20221205061134 AddDisablePatsToApplicationSettings: migrating ==============
main: -- add_column(:application_settings, :disable_personal_access_tokens, :boolean, {:default=>false, :null=>false})
main:    -> 0.0042s
main: == 20221205061134 AddDisablePatsToApplicationSettings: migrated (0.0050s) =====

down

$ rake db:migrate:down:main VERSION=20221205061134                                                                                                                      
main: == 20221205061134 AddDisablePatsToApplicationSettings: reverting ==============
main: -- remove_column(:application_settings, :disable_personal_access_tokens, :boolean, {:default=>false, :null=>false})
main:    -> 0.0048s
main: == 20221205061134 AddDisablePatsToApplicationSettings: reverted (0.0068s) =====

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