Replace use of preference array resources and constants with enums

[bellerbrock]

Discussed here: #986 (comment)

The idea being to replace use of preference array resources and constants

    <string-array name="pref_general_location_acquisition_level_values">
        <item>0</item>
        <item>1</item>
        <item>2</item>
        <item>3</item>
    </string-array>

    <string-array name="pref_general_location_acquisition_level_entries">
        <item>@string/location_level_off</item>
        <item>@string/location_level_study</item>
        <item>@string/location_level_observation_unit</item>
        <item>@string/location_level_observation</item>
    </string-array>

        <ListPreference
            android:icon="@drawable/ic_selection_marker"
            android:key="com.fieldbook.tracker.GENERAL_LOCATION_COLLECTION"
            android:summary="%s"
            android:title="@string/pref_general_location_collection_title"
            android:entries="@array/pref_general_location_acquisition_level_entries"
            android:entryValues="@array/pref_general_location_acquisition_level_values"
            android:defaultValue="1"/>

companion object {
        const val LOCATION_COLLECTION_OFF = 0
        const val LOCATION_COLLECTION_STUDY = 1
        const val LOCATION_COLLECTION_OBS_UNIT = 2
        const val LOCATION_COLLECTION_OBS = 3
    }

with enum classes

package com.fieldbook.tracker.enums

import com.fieldbook.tracker.R

enum class LocationCollectionMode(val value: Int, val labelResId: Int) {
    OFF(0, R.string.location_level_off),
    STUDY(1, R.string.location_level_study),
    OBS_UNIT(2, R.string.location_level_observation_unit),
    OBS(3, R.string.location_level_observation);

    companion object {
        fun fromValue(value: Int): LocationCollectionMode? = values().find { it.value == value }
    }
}

Using the enums to populate preferences programatically something like this (in addition to checking preference values in other parts of the app)

val locationModePreference = findPreference<ListPreference>("com.fieldbook.tracker.GENERAL_LOCATION_COLLECTION")
val locationModes = LocationCollectionMode.values()

locationModePreference?.entries = locationModes.map { getString(it.labelResId) }.toTypedArray()
locationModePreference?.entryValues = locationModes.map { it.value.toString() }.toTypedArray()