Merge all redux actions mutating cryptoStore into one.

Summary:
This differential was created in response to the issue pointed by Ashoat: https://phab.comm.dev/D9532#inline-60290. Cryptographically, it doesn't make
sense in our project to have primaryAccount set but nulled notificationAccount. Additionally it doesn't make sense if there is primaryAccount but there are
no primaryIdentityKeys. That said we need one redux action to set entire CryptoStore at once and this part of redux should either have all fields set all be null.

Test Plan:
Log-in and Log-out while observing Redux extension of Developer Tools. Ensure that LOG_OUT_SUCCESS action succesfully changes CryptoStore to null and
shortly SET_CRYPTO_STORE action is dispatched that correctly sets entire CryptoStore.

Reviewers: atul

Reviewed By: atul

Subscribers: ashoat, tomek, wyilio

Differential Revision: https://phab.comm.dev/D9592