Adds support for appending to an existing Excel table.
# Important Notes
- Renamed `Column_Mapping` to `Column_Name_Mapping`
- Changed new type name to `Map_Column`
- Added last modified time and creation time to `File`.
- Remove `from_xls` and `from_xlsx`.
- Add `headers` support to `File_Format.Excel`.
- Altered default read for Excel to be the first sheet.
- Altered behavior so that single cells grow down and right when reading sheet.
- Altered `Excel_Range` so knows if single cell or 1x1 range address.
# Important Notes
- Renamed `Range` to `Cell_Range` to avoid name clash.
- Read in Excel files following the specification.
- Support for XLSX and XLS formats.
- Ability to select ranges and sheets.
- Skip Rows and Row Limits.
# Important Notes
- Minor fix to DelimitedReader for Windows
- Added Encoding type
- Added `Text.bytes`, `Text.from_bytes` with Encoding support
- Renamed `File.read` to `File.read_text`
- Renamed `File.write` to `File.write_text`
- Added Encoding support to `File.read_text` and `File.write_text`
- Added warnings to invalid encodings
- Added Minimum, Maximum, Longest. Shortest, Mode, Percentile
- Added first and last to Map
- Restructured Faker type more inline with FakerJS
- Created 2,500 row data set
- Tests for group_by
- Performance tests for group_by
