Remove deprecated /indicators/base API aliases

[Copilot]

This PR removes the deprecated /indicators/base API route aliases as requested in the issue, now that NCR and Prefect workflows have been updated to use the /indicators/cmip5 endpoints.

Changes Made

• Removed route decorators for /indicators/base/point/<lat>/<lon> and /indicators/base/area/<var_id> from their respective functions in routes/indicators.py
• Updated cached URLs list in luts.py to remove the deprecated /indicators/base/point/ and /indicators/base/area/ entries
• Cleaned up module docstring to remove outdated reference to "base" indicators

The API now exclusively serves climate indicators data through the /indicators/cmip5/* endpoints, which match the current API documentation. The underlying functionality remains unchanged - only the deprecated URL aliases have been removed.

Impact

• /indicators/base/point/<lat>/<lon> → removed (use /indicators/cmip5/point/<lat>/<lon>/ instead)
• /indicators/base/area/<var_id> → removed (use /indicators/cmip5/area/<var_id>/ instead)
• /indicators/cmip5/* endpoints → unchanged and functional

Fixes #604.

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