Add support to run new feature: light client mode

[lazam]

To support a new feature of Substrate to run the node as light client mode in this PR

[bakhtin]

Please, make sure to re-run pre-commit hooks to fix the README

diff --git a/charts/node/README.md b/charts/node/README.md
index bec6285..7bcd811 100644
--- a/charts/node/README.md
+++ b/charts/node/README.md
@@ -375,7 +375,7 @@ If you're running a collator node:
 | node.lightClientMode | object | `{"enabled":false,"relayChain":"","relayChainCustomChainspecPath":"","relayChainCustomChainspecUrl":""}` | EXPERIMENTAL!!! Run the collator node without a relay chain via light client ref: https://github.com/paritytech/cumulus/pull/2270 Enabling this option will disable the values of collatorRelayChain |
 | node.lightClientMode.enabled | bool | `false` | Enable deployment of the external collator |
 | node.lightClientMode.relayChain | string | `""` | Name of the Relay Chain to connect |
-| node.lightClientMode.relayChainCustomChainspecPath | string | `""` | Path to the file containing the chainspec of the collator relay-chain Set to /chain-data instead of /relaychain-data to avoid  deploying uncessary persitent volume |
+| node.lightClientMode.relayChainCustomChainspecPath | string | `""` | Path to the file containing the chainspec of the collator relay-chain Set to /chain-data instead of /relaychain-data to avoid deploying uncessary persitent volume |
 | node.lightClientMode.relayChainCustomChainspecUrl | string | `""` | URL to retrive custom chain spec |
 | node.logLevels | list | `[]` | Log level |
 | node.perNodeServices | object | `{"apiService":{"annotations":{},"enabled":true,"externalDns":{"customPrefix":"","enabled":false,"hostname":"example.com","ttl":300},"externalTrafficPolicy":"Cluster","httpPort":9933,"prometheusPort":9615,"relayChainPrometheusPort":9625,"rpcPort":9944,"type":"ClusterIP","wsPort":9955},"paraP2pService":{"annotations":{},"enabled":false,"externalDns":{"customPrefix":"","enabled":false,"hostname":"example.com","ttl":300},"externalTrafficPolicy":"Cluster","port":30334,"type":"NodePort","ws":{"enabled":false,"port":30335}},"relayP2pService":{"annotations":{},"enabled":false,"externalDns":{"customPrefix":"","enabled":false,"hostname":"example.com","ttl":300},"externalTrafficPolicy":"Cluster","port":30333,"type":"NodePort","ws":{"enabled":false,"port":30334}},"setPublicAddressToExternalIp":{"enabled":false,"ipRetrievalServiceUrl":"https://ifconfig.io"}}` | Configuration of individual services of the node |

[lazam]

I renamed the two different modes to collatorExternalRelayChain and collatorLightClient to match the same convention of the collatorRelaychain.

[BulatSaif]

Move this {{- end }} up:
Before:

--parachain flags 
{{- if and .Values.node.isParachain (not .Values.node.externalRelayChain.enabled) }}
-- \ 
--relaychain flags
{{- end }}
--common flags  (parachain+relaychain)

Now:

--parachain flags 
{{- if and .Values.node.isParachain (not .Values.node.externalRelayChain.enabled) }}
-- \ 
--new relaychain flags
{{- if  not .Values.node.collatorLightClient.enabled }}
--relaychain flags
{{- end }}
--common flags  (parachain+relaychain)
{{- end }}

expected:

--parachain flags 
{{- if and .Values.node.isParachain (not .Values.node.externalRelayChain.enabled) }}
-- \ 
--new relaychain flags
{{- if  not .Values.node.collatorLightClient.enabled }}
--relaychain flags
{{- end }}
{{- end }}
--common flags  (parachain+relaychain)