Create termux-shared library package for all termux constants and shared utils

The termux plugins should use this library instead of hardcoding "com.termux" values in their source code.

The library can be included as a dependency by plugins and third party apps by including the following line in the build.gradle where x.xxx is the version number, once its published.

`implementation 'com.termux:termux-shared:x.xxx'`

The `TermuxConstants` class has been updated to `v0.17.0`, `TermuxPreferenceConstants` to `v0.9.0` and `TermuxPropertyConstants` to `v0.6.0`. Check their Changelog sections for info on changes.

Some typos and redundant code has also been fixed.

termux-shared/src/main/java/com/termux/shared/packages/PackageUtils.java

@@ -0,0 +1,110 @@
+package com.termux.shared.packages;
+
+import android.content.Context;
+import android.content.pm.ApplicationInfo;
+import android.content.pm.PackageInfo;
+
+import androidx.annotation.NonNull;
+
+import com.termux.shared.logger.Logger;
+
+public class PackageUtils {
+
+    /**
+     * Get the {@link Context} for the package name.
+     *
+     * @param context The {@link Context} to use to get the {@link Context} of the {@code packageName}.
+     * @return Returns the {@link Context}. This will {@code null} if an exception is raised.
+     */
+    public static Context getContextForPackage(@NonNull final Context context, String packageName) {
+        try {
+            return context.createPackageContext(packageName, Context.CONTEXT_RESTRICTED);
+        } catch (Exception e) {
+            Logger.logStackTraceWithMessage("Failed to get \"" + packageName + "\" package context.", e);
+            return null;
+        }
+    }
+
+    /**
+     * Get the {@link PackageInfo} for the package associated with the {@code context}.
+     *
+     * @param context The {@link Context} for the package.
+     * @return Returns the {@link PackageInfo}. This will be {@code null} if an exception is raised.
+     */
+    public static PackageInfo getPackageInfoForPackage(@NonNull final Context context) {
+        try {
+            return context.getPackageManager().getPackageInfo(context.getPackageName(), 0);
+        } catch (final Exception e) {
+            return null;
+        }
+    }
+
+    /**
+     * Get the app name for the package associated with the {@code context}.
+     *
+     * @param context The {@link Context} for the package.
+     * @return Returns the {@code android:name} attribute.
+     */
+    public static String getAppNameForPackage(@NonNull final Context context) {
+        return context.getApplicationInfo().loadLabel(context.getPackageManager()).toString();
+    }
+
+    /**
+     * Get the package name for the package associated with the {@code context}.
+     *
+     * @param context The {@link Context} for the package.
+     * @return Returns the package name.
+     */
+    public static String getPackageNameForPackage(@NonNull final Context context) {
+        return context.getApplicationInfo().packageName;
+    }
+
+    /**
+     * Get the {@code targetSdkVersion} for the package associated with the {@code context}.
+     *
+     * @param context The {@link Context} for the package.
+     * @return Returns the {@code targetSdkVersion}.
+     */
+    public static int getTargetSDKForPackage(@NonNull final Context context) {
+        return context.getApplicationInfo().targetSdkVersion;
+    }
+
+    /**
+     * Get the {@code versionName} for the package associated with the {@code context}.
+     *
+     * @param context The {@link Context} for the package.
+     * @return Returns the {@code versionName}. This will be {@code null} if an exception is raised.
+     */
+    public static Boolean isAppForPackageADebugBuild(@NonNull final Context context) {
+        return ( 0 != ( context.getApplicationInfo().flags & ApplicationInfo.FLAG_DEBUGGABLE ) );
+    }
+
+    /**
+     * Get the {@code versionCode} for the package associated with the {@code context}.
+     *
+     * @param context The {@link Context} for the package.
+     * @return Returns the {@code versionCode}. This will be {@code null} if an exception is raised.
+     */
+    public static Integer getVersionCodeForPackage(@NonNull final Context context) {
+        try {
+            return getPackageInfoForPackage(context).versionCode;
+        } catch (final Exception e) {
+            return null;
+        }
+    }
+
+    /**
+     * Get the {@code versionName} for the package associated with the {@code context}.
+     *
+     * @param context The {@link Context} for the package.
+     * @return Returns the {@code versionName}. This will be {@code null} if an exception is raised.
+     */
+    public static String getVersionNameForPackage(@NonNull final Context context) {
+        try {
+            return getPackageInfoForPackage(context).versionName;
+        } catch (final Exception e) {
+            return null;
+        }
+    }
+
+}