Add ability to run manage from the serve command

[mattnibs]

This commit adds the ability to run zed manage in the same process as the zed serve command. If the -manage flag is set with a duration greater than 0 manage will run.

This commit also move the manage package to lake/api/manage package and simplifies the logic for the monitor function.

[nwt]

I'd like to have @philrz give this a spin before we merge it.

[mattnibs]

I'd like to have @philrz give this a spin before we merge it.

Agreed.

[philrz]

I just tested this branch out at commit 9ce0f4f and it seems to work fine. One thing I found a little odd though is that I went looking for a ztest in this PR since that usually gives me a starting point for seeing how the new functionality is invoked and it looks like the only ztest change is to something that only exercises the pre-existing approach that used the zed manage approach. Does the continuous nature of zed serve -manage make it too difficult to hit with ztest?

[mattnibs]

@philrz yes

[philrz]

After an offline discussion with @nwt he agreed to take up the testing angle separately/later via what's now tracked in #5024.