Add support for customizable base option and auto appending .svg extension

[iamjaeholee]

Description

Currently, the src base is set to the public directory, but I think it would be useful to add an option that allows users to customize the base directory.

Why?

• Some users might prefer to store SVG assets within the src folder instead of the public directory.
• Even when using the public directory, assets are often organized within an assets folder, so having to specify paths like assets/svgname.svg repeatedly can be inconvenient.

Proposal

1. Introduce a base option to set a custom directory from which SVGs are resolved. This way, users can easily define where their SVG files are located.
2. Allow users to reference SVGs without explicitly including the .svg extension. For example, typing svgname would automatically resolve as svgname.svg.

Benefits

• Improved flexibility for asset organization.
• Enhanced developer experience with shorter and more intuitive path references.

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If this proposal sounds good, I'd like to take a stab at implementing it. What do you think?