add darkmode config

[bradleyandrick]

Related Issue(s):

• NA

Proposed Changes:

1. Add basemap dark theme configuration variable
   • This was needed so that a custom basemap could be set & still override the style to dark mode while showing custom BASEMAP_HTML_ATTRIBUTION text value
2. Add logo max-height

BONUS:

3. Resolve security issue coming from babel

To test

• make sure BASEMAP_DARK_THEME is not in config
• load app
• confirm basemap defaults to dark mode
• stop app
• add BASEMAP_DARK_THEME: true to config
• load app
• confirm basemap defaults to dark mode
• stop app
• add BASEMAP_DARK_THEME: false to config
• load app
• confirm basemap uses provider default style (should show colors)

PR Checklist:

• [X] I have added my changes to the CHANGELOG or a CHANGELOG entry is not required.