Improve the messaging around `brew install` when there's a possible user
action such as an `upgrade` or `link` and don't tell people to
`install --force` when it's unnecessary.

While I did this, tweak the output and function usage in a couple of
related places.

Some example output before this change:
```
Warning: openssl is a keg-only and another version is linked to opt.
Use `brew install --force` if you want to install this version
Warning: mysql@5.6 is a keg-only and another version is linked to opt.
Use `brew install --force` if you want to install this version
Warning: analog-6.0_1 already installed
Warning: bash-completion@2-2.5 already installed, it's just not linked.
```

Some example output after this change:
```
Error: openssl 1.0.2k is already installed
To upgrade to 1.0.2l, run `brew upgrade openssl`
Warning: mysql@5.6 5.6.36_1 is already installed
Warning: analog 6.0_1 is already installed
Warning: bash-completion@2 2.5 is already installed, it's just not linked.
You can use `brew link bash-completion@2` to link this version.
```

These formulae are detected as missing but exist in an unreadable form.

Fixes #2485

For example if this is for a really old keg, keg where a user has
manually removed stuff or used `brew diy`.

These methods belong together so combine them in a single class to
provide a simpler API.

This will allow extending this class so it can be used by more than
just blacklisting.

Partial implementation of
https://github.com/Homebrew/brew-evolution/pull/15, along with the ability to
search for deleted formulae in git history (inspired by #1996) which is not
described in the proposal.

See also: #1371.

These can now be done with just `brew upgrade`, like other upgrades.

Fixes #1818.

When reproducing issues with software that hasn’t been bottled yet on
your version of macOS it can sometimes be helpful to use `or_later`
bottle functionality i.e. just use the bottle for the latest version of
macOS available. This maps well to the existing `--force-bottle`
argument so it will now act as if the latest bottle has a `or_later`
ending.

* installing HEAD keg_only should be possible only if:
  1.
    - Old version installed differs from new one and optlinked
    - `--force` flag is passed
    - HEAD is seriously outdated or outdated with `--fetch-HEAD`
  or 2.
    - Old version installed differs from new one and not optlinked
  or 3.
    - This formula is not installed

* installing keg_only should be possible only if:
  1.
    - Old version installed differs from new one and optlinked
    - `--force` flag is passed
  or 2.
    - Old version installed differs from new one and not optlinked
  or 3.
    - This formula is not installed

* installing HEAD should be possible only if:
  1.
    - Old HEAD is seriously outdated or outdated with `--fetch-HEAD`
  or 2.
    - HEAD is not installed

* installing stable or devel should be possible only if:
  - Old version installed differs from new one

New name is HOMEBREW_CASK_TAP_CASK_REGEX

This is no longer relevant after moving to taps/tags and if ever
re-added it should probably target homebrew/core.

Fixes #1194.

Not quite a mass replacement as I've used OS X and Mac OS X where
describing specific older versions and added compatibility methods
for things in the DSL.

Better use the abstraction layer so e.g. Linux could have similarly
fatal checks for these things.

`any?` is not the opposite of `empty?`. Besides the case that
`[false, nil].any?` will return false, `any?`(O(n)) has much worse
performance than `empty?`(O(1)).

This is a developer-only option I created for testing purposes. It
should not be used by end-users.

Closes #411.

Signed-off-by: Xu Cheng <xucheng@me.com>