import format_width and format_digits for SAS

[belegdol]

Please read the README, particularly the known limitations section!

Describe the issue
Currently, meta.original_variable_types only contains the format names but not their widths. Looking at https://github.com/WizardMac/ReadStat/blob/05cadd8906f6cbd4ac22966d1f4b0ae2743ae8bf/src/sas/readstat_sas7bdat_read.c#L23-L24, it appears that readstat can read the latter.

To Reproduce
Import a sas dataset created with a format such as b8601da8. or 10.2.

File example
Not currently possible but any file should do.

Expected behavior
A clear and concise description of what you expected to happen.

Setup Information:
How did you install pyreadstat? pip
Platform (windows, macOS, linux, 32 or 64 bit): any
Python Version 3.11
Python Distribution (System, plain python, Anaconda): plain python
Using Virtualenv or condaenv? venv

[belegdol]

This could in theory make integer identification possible (#295). Saurfang (https://github.com/saurfang/spark-sas7bdat) does it by checking format width and precision:

• inferInt (Default: false)
  • Boolean: infer numeric columns with <=4 bytes, format width >0 and format precision =0, as Int
• inferLong (Default: false)
  • Boolean: infer numeric columns with <=8 bytes, format width >0 and format precision =0, as Long
• inferShort (Default: false)
  • Boolean: infer numeric columns with <=2 bytes, format width >0 and format precision =0, as Short

[belegdol]

At the first glance it looks like the following change might be sufficient:
WizardMac/ReadStat#361