feat: custom log rotation duration

[gibbz00]

This PR attempts to get #2654 past the finish line, as it seems to have gone stale. I'll refrain from repeating its motivation and solution sections if that's ok.

Closes: #778,#2654

Version control:

1. Rebased on current master.
2. Removed merge commits
3. Squashed PR commits

Changes:

1. Rotation::custom uses std::time::Duration. This removes the need for users to pull in the time library, whilst simultaneously ensuring that the duration is always positive.

Improvements:

1. Add a test that verifies that an overflow of more than 10 years results in an error.
2. Added a public rolling::custom() constructor for RollingFileAppender
3. Expanded the documentation.

[kadenlnelson]

Do you think that the constant intervals (minutely, hourly, etc.) should be wrappers around this new custom interval?

I'm wondering if it would simplify other functions like next_date and date_format, particularly the match statements.

[stegaBOB]

Do you think that the constant intervals (minutely, hourly, etc.) should be wrappers around this new custom interval?

I'm wondering if it would simplify other functions like next_date and date_format, particularly the match statements.

When I initially implemented this that thought never came to mind. I think this is a great idea! I think it should be possible to do without a breaking change as well. The time crate has constant durations for the intervals we'd want.

[kadenlnelson]

LGTM The refactoring that I mentioned in my previous review could be done in a separate PR.

@hawkw it looks like @zekisherif doesn't have write access to the repository and he's the code owner for these files. May you take a pass at this PR or recommend another individual for review?

[gibbz00]

Do you think that the constant intervals (minutely, hourly, etc.) should be wrappers around this new custom interval?
LGTM The refactoring that I mentioned in my previous review could be done in a separate PR.

I have some minutes to spare this morning, can take a look at it right now if that's ok 😊