Major code refactoring

Main goals are:
1. Ability to use mocks in unit tests instead of
having to setup mock web server as if it was an
integration test.
2. Cache Retrofit services in memory
3. Make it easier to read
4. Use OptIn where possible instead of propagating
Experimental* annotations everywhere

app/src/main/java/gq/kirmanak/mealient/ui/ViewExtensions.kt

@@ -20,7 +20,7 @@ import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.callbackFlow
 import timber.log.Timber
 
-@ExperimentalCoroutinesApi
+@OptIn(ExperimentalCoroutinesApi::class)
 fun SwipeRefreshLayout.refreshesLiveData(): LiveData<Unit> {
     val callbackFlow: Flow<Unit> = callbackFlow {
         val listener = SwipeRefreshLayout.OnRefreshListener {
@@ -63,7 +63,7 @@ fun AppCompatActivity.setActionBarVisibility(isVisible: Boolean) {
         ?: Timber.w("setActionBarVisibility: action bar is null")
 }
 
-@ExperimentalCoroutinesApi
+@OptIn(ExperimentalCoroutinesApi::class)
 fun TextView.textChangesFlow(): Flow<CharSequence?> = callbackFlow {
     Timber.v("textChangesFlow() called")
     val textWatcher = doAfterTextChanged {

app/src/main/java/gq/kirmanak/mealient/ui/auth/AuthenticationFragment.kt

@@ -16,12 +16,10 @@ import gq.kirmanak.mealient.R
 import gq.kirmanak.mealient.data.auth.impl.AuthenticationError.*
 import gq.kirmanak.mealient.databinding.FragmentAuthenticationBinding
 import gq.kirmanak.mealient.ui.textChangesFlow
-import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.flow.filterNotNull
 import kotlinx.coroutines.flow.first
 import timber.log.Timber
 
-@ExperimentalCoroutinesApi
 @AndroidEntryPoint
 class AuthenticationFragment : Fragment(R.layout.fragment_authentication) {
     private val binding by viewBinding(FragmentAuthenticationBinding::bind)

app/src/main/java/gq/kirmanak/mealient/ui/recipes/RecipesFragment.kt

@@ -15,11 +15,9 @@ import gq.kirmanak.mealient.data.recipes.db.entity.RecipeSummaryEntity
 import gq.kirmanak.mealient.databinding.FragmentRecipesBinding
 import gq.kirmanak.mealient.ui.auth.AuthenticationViewModel
 import gq.kirmanak.mealient.ui.refreshesLiveData
-import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.flow.collect
 import timber.log.Timber
 
-@ExperimentalCoroutinesApi
 @AndroidEntryPoint
 class RecipesFragment : Fragment(R.layout.fragment_recipes) {
     private val binding by viewBinding(FragmentRecipesBinding::bind)