Add support for passing params to render command

[DannyBen]

• Drop support for Ruby 3.1
• Change convert usage pattern:

  - victor convert SVG_FILE [RUBY_FILE]
  + victor convert SVG_FILE [--save RUBY_FILE]

• Change render usage pattern:

  - victor render RUBY_FILE [SVG_FILE]
  + victor render RUBY_FILE [options] [PARAMS...]

• Add support for supplying key=value pairs to the render command. These will be available inside the params hash in the Ruby script.