Cached tiles fail to load when using the executable

[erodarob]

Description:

Cached tiles are placed in a directory not available to the frontend when the app is run through the executable. This prevents cached tiles from loading, while tiles loaded from the tile provider still work.

Tasks:

• [x] Add a check for whether the app is running from the executable or in a development environment (eg using npm start). This may need to be communicated from the main process to the frontend.
• [x] Utilize this check to switch the file path where cached tiles are stored. It should be "resources/app/src/cachedtiles" from the executable and "src/cachedtiles" in a development environment.

Notes:

It may also be possible to fix this bug by changing the file paths from "./src/cachedtiles" to "src/cachedtiles". The relevant lines of code include line 240-341 in main.js

[erodarob]

Figured out the root cause of the issue was that some file paths were using "/" or "./" instead of "dirname" so they were placing files in the wrong spot. This fixed the tile loading issue and I went through and made all the other file paths consistent using "./" for files that should be placed in the same directory as the executable and "dirname" with path.join for files that should be placed relative to main.js.