Switch to compose state and kotlin flows - 4. iteration (#318)

* Moved composables

Signed-off-by: Arnau Mora Gras <arnyminerz@proton.me>

* Moved model

Signed-off-by: Arnau Mora Gras <arnyminerz@proton.me>

* Added flow

Signed-off-by: Arnau Mora Gras <arnyminerz@proton.me>

* Moved model and composables

Signed-off-by: Arnau Mora Gras <arnyminerz@proton.me>

* Renamed instance state

Signed-off-by: Arnau Mora Gras <arnyminerz@proton.me>

* Migrated Add Calendar Activity

Signed-off-by: Arnau Mora Gras <arnyminerz@proton.me>

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Signed-off-by: Arnau Mora Gras <arnyminerz@proton.me>