Add aliasing API types

[jClugstor]

Checklist

• [ x] Appropriate tests were added
• [ x] Any code changes were done in a way that does not break public API
• [ x] All documentation related to code changes were updated
• [ x] The new code follows the
  contributor guidelines, in particular the SciML Style Guide and
  COLPRAC.
• [ x] Any new documentation only uses public API

Additional context

This adds the abstract type AbstractAliasSpecifier and the concrete subtypes ODEAliases and LinearAliases meant to hold information on which variables to alias when solving the problems. When an alias specifier is true, that variable is aliased, and vice versa for false. When the alias specifier is nothing, the solvers default behavior is used.

Also bumps the minor version since this is a new feature.