Add ability to install rbenv independently

- Can now install rbenv separately. Can be used as a requirement in a
  state for installing rbenv plugins using the git or file states
Fix description of method and whitespace lost
Add event function to state runner for light event interaction via CLI
lxc: saltify -> bootstrap; lxc & seed: doc improvements
salt.modules.seed: typo
blockreplace: append_if_not_empty ensure \n before mark
Fix master._clear_old_jobs for ext_pillars with root parameter
Revert "Fix #11003 TypeError: can only concatenate list (not "ImmutableLazyProxy(list)") to list"

This reverts commit 50fe12a5f515e3bb37ea0df7222b5c8c61229b63.
`ImmutableList`'s should also support `__radd__`. Fixes #11003.
Spelling correction: exttermal > external
Merge pull request #11086 from krak3n/fix-master._clear_old_jobs-ext_pillar-root

Fix master._clear_old_jobs for ext_pillars with root parameter
Clarify when the new "root" param for git_pillar will be added
remove stale comments
Merge pull request #11092 from mgwilliams/lxc

lxc: saltify -> bootstrap; lxc & seed: doc improvements
Started some integration tests for mac_user module
refactor some method names in stack to be more consistent
Merge pull request #11091 from terminalmage/docs

Clarify when the new "root" param for git_pillar will be added
Refactor name of server for each stack to .server since udp or uxd is redundant as the type is
determined by the stack
Rnamed UxdTxes to txes UxdRxes to rxes since type is given by the stack type name is redundant
Renamed udpTxes to txes UdpRxes to rexes since type is given the the stack type, name is redunant
Add test case which triggers #11003.