[llvm-strings] Switch command line parsing from llvm::cl to OptTable

Some behavior changes:

* `-t=d` is removed. Use `-t d` instead.
* one-dash long options like `-all` are supported. Use `--all` instead.
* `--all=0` or `--all=false` cannot be used. (Note: `--all` is silently ignored anyway)
* `--help-list` is removed. This is a `cl::` specific option.

Nobody is likely leveraging any of the above.

Advantages:

* `-t` diagnostic gets improved.
* in the absence of `HideUnrelatedOptions`, `--help` will not list unrelated options if linking against libLLVM-13git.so or linker GC is not used.
* Decrease the probability of cl::opt collision if we do decide to support multiplexing

Note: because the tool is so simple, used more for forensics instead of a building
tool, and its long options are unlikely used in one-dash form, I just drop the
one-dash form in this patch.

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D104889