Introduce autoTitleRightAlign column flag

[cgzones]

Instead of handling PERCENT_CPU as a special case for whether to align the title of a dynamically sized column to the right or the left introduce a new flag, which can be reused by other columns.

Split from #1288

/cc @Explorer09

[Explorer09]

My concerns about the autoTitleRightAlign flag are these:

1. There is only one user of the flag in this commit. Generally we shouldn't introduce a flag when there is only one user using it.
2. If a column needs to be right-aligned, the alignment would likely apply to not just the title, but the data cells as well. (It won't make sense to just right align the title and not the data.)

[cgzones]

Applied via https://github.com/htop-dev/htop/commit/cbcfc5f7d08e210a3477071607a3195fa31f06a3