Hammer CLI

Few places [1], [2] in hammer core inject @context variable into field parameters. Although only :show_ids flag is used in formatters afterwards. There is no actual value to have such global variable accessible in formatters. This also leads to

Error: singleton can't be dumped

after https://github.com/theforeman/hammer-cli/commit/c8430df12d28856abcdb9ca076040ca9cbe72c8c patch.

[1] - https://github.com/theforeman/hammer-cli/blob/c8430df12d28856abcdb9ca076040ca9cbe72c8c/lib/hammer_cli/output/adapter/base.rb#L79
[2] - https://github.com/theforeman/hammer-cli/blob/c8430df12d28856abcdb9ca076040ca9cbe72c8c/lib/hammer_cli/output/adapter/tree_structure.rb#L58