feat: adding ability for for charts to be pulled with plain HTTP (#1672)

* eat: adding ability for for charts to be pulled without HTTPS

accomplished by:

- Adding PlainHttp attribute to RepositorySpec., HelmDefault, ReleaseSpec
- Adding UnitTests for getOCIChart Flags.
- Adding funciton and unitTests for getChartDownload
- Changing and refactoring how Flags are added to getOCIChart.

Resolves #1224

Signed-off-by: Peter Halliday <peter.halliday@servicenow.com>

* Pass PlainHttp to OCI repo options, fix unit test

Signed-off-by: Pascal Rivard <privard@rbbn.com>

* Fix doc

Signed-off-by: Pascal Rivard <privard@rbbn.com>

* Use repository fields in non-OCI chart download options

Signed-off-by: Pascal Rivard <privard@rbbn.com>

* Update hashes in TestGenerateID

Signed-off-by: Pascal Rivard <privard@rbbn.com>

* Make sure repo exists when using its options

Signed-off-by: Pascal Rivard <privard@rbbn.com>

* Do not add TLS options if PlainHttp is set, adapt unit tests

Signed-off-by: Pascal Rivard <privard@rbbn.com>

* Fix doc

Signed-off-by: Pascal Rivard <privard@rbbn.com>

* Remove 'else if' from appendChartDownloadFlags

Signed-off-by: Pascal Rivard <privard@rbbn.com>

---------

Signed-off-by: Peter Halliday <peter.halliday@servicenow.com>
Signed-off-by: Pascal Rivard <privard@rbbn.com>
Co-authored-by: Peter Halliday <peter.halliday@servicenow.com>
Co-authored-by: Pascal Rivard <privard@rbbn.com>

docs/index.md

@@ -161,6 +161,10 @@ repositories:
 - name: skipTLS
   url: https://ss.my-insecure-domain.com
   skipTLSVerify: true
+# Advanced configuration: Connect to a repo served over plain http
+- name: plainHTTP
+  url: http://just.http.domain.com
+  plainHttp: true
 
 # context: kube-context # this directive is deprecated, please consider using helmDefaults.kubeContext
 
@@ -223,6 +227,8 @@ helmDefaults:
   cascade: "background"
   # insecureSkipTLSVerify is true if the TLS verification should be skipped when fetching remote chart
   insecureSkipTLSVerify: false
+  # plainHttp is true if fetching the remote chart should be done using HTTP
+  plainHttp: false
   # --wait flag for destroy/delete, if set to true, will wait until all resources are deleted before mark delete command as successful
   deleteWait: false
   # Timeout is the time in seconds to wait for helmfile destroy/delete (default 300)
@@ -339,6 +345,8 @@ releases:
     cascade: "background"
     # insecureSkipTLSVerify is true if the TLS verification should be skipped when fetching remote chart
     insecureSkipTLSVerify: false
+    # plainHttp is true if fetching the remote chart should be done using HTTP
+    plainHttp: false
     # suppressDiff skip the helm diff output. Useful for charts which produces large not helpful diff, default: false
     suppressDiff: false
     # suppressOutputLineRegex is a list of regex patterns to suppress output lines from helm diff (default []), available in helmfile v0.162.0