id_for_municipality and related functions

[CarwilB]

Add Municipality ID Lookup Functionality

This PR adds comprehensive municipality ID lookup functionality to the package, including:

• New functions to get municipality IDs based on names: id_for_municipality() and id_for_municipality_2()
• Functions to retrieve municipality, province, and department names from IDs
• Support for handling alternative municipality spellings and name variations
• Added .DS_Store to .gitignore

Data Resources

• Added anexo_municipios dataset containing official municipality information
• Created muni_id_lookup_table with alternative municipality names and mappings
• Added muni_gb2014_conversion and muni_gb2014_lookup tables for GB2014 format compatibility

Helper Functions

• rename_anexo_columns() for standardizing column names
• str_equivalent_list() for checking string equivalence in lists
• add_id_for_municipality() to add municipality IDs to datasets

Testing

• Comprehensive test suite for all new municipality lookup functionality
• Tests for edge cases like non-existent municipalities and duplicate names

[CarwilB]

• id_for_municipality and related functions #5 👈 (View in Graphite)
• main

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