Add a method to save TableReports to a file

[jeromedockes]

Problem Description

mentioned in this comment: should we have a slightly easier way to save a tablereport to a file?

Feature Description

report = TableReport(df)

we could do

report.write("/tmp/report.html")

or maybe report.save

instead of

with open("/tmp/report.html", "w", encoding="utf-8") as f:
    f.write(report.html())

[mrastgoo]

I am working on it