Remove deprecated command line flags

[ligi]

Rationale

• simplification
• subtraction
• decrease complexity

This also includes:

• we need to update puppeth as it is still using them
• remove dead code paths
• update documentation

[DGKSK8LIFE]

I'd be willing to make a PR fix for this! Let me make a list of deprecated geth flags and go from there.

[renaynay]

Awesome @DGKSK8LIFE. Deprecated flags to be removed are located under the show-deprecated-flags command. Hope that helps!

[DGKSK8LIFE]

Now that I look at the codebase, this is a larger undertaking than I initially speculated. I also need some help navigating it. There's lots of interdependence within the code. Maybe I could open a draft PR and then we could work on addressing this issue from there?

[DGKSK8LIFE]

And if not, could someone explain where everything is in Ethereum's codebase related to flags? Thanks. (sorry I'm a new contributor to geth so don't completely understand its codebase yet)

[DGKSK8LIFE]

What do you think about the draft PR suggestion? @ligi

[ligi]

I think you should do something else then (e.g. test if #22145 works instead of telling others to do so)
IMHO when wanting to contribute in this project you should be familiar with the codebase or at least know how to get familiar.
I also think you should stop approving PRs when you are not familiar with the codebase.

[renaynay]

Can we already deprecate most of the flags in the aliased section? Some where removed in May 2020