fix: Feedback(3) addressed by adding installation guide, adding example in usage and providing basic definition to outputs on README

[dorisyycai]

• added package installation section
• updated usage section to include example of how
• updated summary section to provide basic definitions to the output financial metrics

linked to: https://github.com/UBC-MDS/quanteda/issues/79 https://github.com/UBC-MDS/quanteda/issues/71 https://github.com/UBC-MDS/quanteda/issues/69

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (c0e6066) 90.47% compared to head (db13b41) 90.47%. Report is 4 commits behind head on main.

:exclamation: Current head db13b41 differs from pull request most recent head 948e297. Consider uploading reports for the commit 948e297 to get more accurate results

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #87 +/- ## ======================================= Coverage 90.47% 90.47% ======================================= Files 5 5 Lines 63 63 ======================================= Hits 57 57 Misses 6 6 ```

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