Fix SVG loaders for SSR targets

[homer0]

What does this PR do?

When a Node target was building a browser target files, it would handle SVG files as both fonts and images, because the RegExp on the loaders are specific to the target being processed.

This fix add listeners for the fonts and images rules in order to include the paths for the SSR targets.

This is a breaking change because I changed a few properties and methods of the main service.

On the next major release I'll make most of the methods and properties private so changes like these won't be breaking, there's no reason to use the service outside the plugin.

How should it be tested manually?

yarn test
# or
npm test

[coveralls]

Pull Request Test Coverage Report for Build 19

• 34 of 34 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

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Totals
Change from base Build 17:	0.0%
Covered Lines:	94
Relevant Lines:	94

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💛 - Coveralls