issue:#1229 Add multi-keyword search

[FriteSansSel]

Added Multi-Keyword Search Capability

Support for multi-keyword search:
The search in command cli.py has been updated to accept a list of search terms
(SEARCH_STRINGS) instead of a single term (SEARCH_STRING). This allows users
to search for events matching one or more specified keywords.

Key Changes:

Replaced search_string argument:
The single search_string argument has been replaced with search_strings,
enabling variable-length keyword input (nargs=-1).
Each search term is processed in a loop, and matching results are added to a
unified set of events.

Consolidation of search results:
Events matching each keyword are combined using a set (all_events) to eliminate
duplicates.
A new event_set is introduced to ensure that events with identical descriptions
are displayed only once.
The final results are sorted and displayed.