Fix missing texture image & epub ebook url for subdirectory support

[mikiher]

Brief summary

Fixes a missing texture image in the nuxt build.

Which issue is fixed?

This addresses this comment in #385

Fixes #3865

In-depth Description

assets/app.css contained a direct url link to /textures/wood_default.jpg. This breaks subdirectory support. Changed this to ~static/textures/wood_default.jpg so it is picked and served by _nuxt (like other urls in the .css files)

How have you tested this?

Ran against a dev server. The texture image is now fetched successfully from /audiobookshelf/_nuxt/img/wood_default.6d366e7.jpg instead of /textures/wood_default.jpg.

[advplyr]

Looks like we missed adding base path to ebooks #3865

[advplyr]

We missed the get library request in store/libraries.js

https://discord.com/channels/942908292873723984/1006652923306066040/1330879198520283156

I'll be at my desk in an hour or so and can put these in just want to document

[advplyr]

That issue in discord may have to do with #3780 actually

[nichwall]

That issue in discord may have to do with #3780 actually

If so, I think we can just roll back that PR to add case insensitivity to the path matching because it was just a CodeQL warning, and look at a resolution more later.

[advplyr]

Ah yeah I see why it happened now because some users have uppercase UUID's and when we lowercase the url the UUID no longer matches in queries.
Although I have no idea how they got an uppercase UUID

[advplyr]

The only other change for subdir support was to add the router base path to epub url because epub.js isn't using axios.
For the UUID issue I just reverted #3780

[mikiher]

Thanks for fixing the epub bug!