This is a minor refactor to move a leftover from Ancient Helm into the
current design. Specifically, the code to install Tiller from the Helm
client is now in `cmd/helm/installer`.

Closes #1033

ref(kube): delete skips IsNotFound errs

Currently, delete returns an error if a resource is not found.
That is a bit confusing because if you delete something that
is not found, the end state is not really an error. The end
state is what you wanted to do in the first place. This type
of error is not propogated from the kube client but it is logged
in tiller.  We could also change this to keep returning errors
(even the not found) and filter it out in the release server.

Add purge option for completely remove a release from tiller

ref(*): return resource update errors

Resolves #1058

fix(cmd): s/accomodate/accommodate/

feat(pkg/provenance): add OpenPGP signatures

Matt's second offence.

fix(helm): remove extra linter output

This adds the --verify and --keyring flags to:

helm fetch
helm inspect
helm install
helm upgrade

Each of these commands can now make cryptographic verification a
prerequisite for using a chart.

This adds support for OpenPGP signatures containing provenance data.
Such information can be used to verify the integrity of a Chart by
testing that its file hash, metadata, and images are correct.

This first PR does not contain all of the tooling necessary for
end-to-end chart integrity. It contains just the library.

See #983

Closes #1076

feat(chart): support 'image:URL' in charts.

Closes #1034

add docs table of contents and update quick start

Add --set flag to `helm upgrade`

Signed-off-by: Jess Frazelle <me@jessfraz.com>

docs(notes.txt): Add NOTES.txt to Chart spec, and describe chart documentation files

feat(tiller): limit the max len of Release.Name

fix(tiller): upgrade Sprig to 2.5.0

Fix #1070

We need this specifically for trimSuffix.

Closes #1071

This limits the number of characters in a release name to 14. This
preserves 10 characters for customizing the `name:` field in charts.

Relates to #1071

feat(helm): add rollback cmd

Disable validateQuotes linter rule

simplify example container names

This encourages people from making container names depend on release
names.

Add note on installation via cask to README.

update readme example and change repository to https

Include values from both --set and --values when specified on install