Implement Proper "View Images in Gallery" Button Functionality

[SamithaKosanam]

Description

After extracting image(s) from a PDF, the "View Images in Gallery" button would fail to actually show the extracted images in the Gallery. This change makes this button functional by putting the correct image content in the URI, which was done by building on a previous pull request that made acceptable changes to the ImageUtils.java file, but this change also adds changes to the FileUtils.java file, as well as the PdfToImageFragment.java file.

Fixes #1058

Type of change

Just put an x in the [] which are valid.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Please describe the tests that you ran to verify your changes.

• ./gradlew assembleDebug assembleRelease
• ./gradlew checkstyle

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings

[codeclimate]

Code Climate has analyzed commit 8bf09a8 and detected 1 issue on this pull request.

Here's the issue category breakdown:

Category	Count
Complexity	1

View more on Code Climate.

[Swati4star]

Can you fix the merge conflicts?