feat(frontends/lean): remove tactic hints for specific classes

The idea is to separate class-instance resolution and tactic framework
as two independent engines.
refactor(frontends/lean/tactic_hint): simplify tactic_hints
fix(bin/linja): add 'all' to phony target; allow multiple phony targets
fix(shell/lean.cpp): print git commit in version string only when it's available
feat(src): add LEAN_VERSION_PATCH
chore(CMakeLists.txt): standard_lib target generates TAGS for library
fix(CMakeLists.txt): rename EMACS_LIB to EMACS_LISP_DIR (default: share/eamcs/site-lisp/lean)
feat(CMakeLists.txt): install lean library to LIBRARY_DIR (default: lib/lean)