feat(keychain)!: remove atom factory

[diegomura]

Removes atom factory from keychain feature package. This now lives in @exodus/keychain-atoms. Reasons explained in https://github.com/ExodusMovement/exodus-hydra/pull/5486 as well:

• If keychain ends up being extracted to a "wallet process", this makes sense to be extracted so the application side does not need to import keychain (import still required for keys, but that might also be convenient to change)
• Keychain is the only feature that holds atom factories. We separated fusion ones out of fusion on @exodus/fusion-atoms, so this follows the same pattern
• All atom factories close to each other

[diegomura]

@mvayngrib CI fails for not found actions. Are you able to merge in the meantime?

[mvayngrib]

@diegomura please rebase

[diegomura]

@mvayngrib done!