GetAllSecrets docs

Signed-off-by: Gustavo Carvalho <gustavo.carvalho@container-solutions.com>

docs/guides-getallsecrets.md

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+# Fetching information from multiple secrets
+
+In some use cases, it might be impractical to bundle all sensistive information into a single secret, or even it is not possible to fully know a given secret name. In such cases, it is possible that an user might need to sync multiple secrets from an external provider into a single Kubernetes Secret. This is possible to be done in external-secrets with the `dataFrom.find` option.
+
+!!! note
+    The secret's contents as defined in the provider are going to be stored in the kubernetes secret as a single key. Currently, it is not possible to apply any decoding Strategy during a find operation.
+
+
+### Fetching secrets matching a given name pattern
+To fetch multiple secrets matching a name pattern from a common SecretStore you can apply the following manifest:
+```yaml
+{% include 'getallsecrets-find-by-name.yaml' %}
+```
+
+Suppose we contain secrets `/path/key1`, `key2/path`, and `path/to/keyring` with their respective values. The above YAML will produce the following kubernetes Secret:
+
+```yaml
+_path_key1: Cg==
+key2_path: Cg==
+path_to_keyring: Cg==
+```
+### Fetching secrets matching a set of metadata tags
+To fetch multiple secrets matching a name pattern from a common SecretStore you can apply the following manifest:
+```yaml
+{% include 'getallsecrets-find-by-tags.yaml' %}
+```
+This will match any secrets containing all of the metadata labels in the `tags` parameter. At least one tag must be provided in order to allow finding secrets by metadata tags.
+
+
+### Searching only in a given path
+Some providers supports filtering out a find operation only to a given path, instead of the root path. In order to use this feature, you can pass `find.path` to filter out these secrets into only this path, instead of the root path.
+
+### Avoiding name conflicts
+By default, kubernetes Secrets accepts only a given range of characters. `Find` operations will automatically replace any not allowed character with a `_`. So if we have a given secret `a_c` and `a/c` would lead to a naming conflict. 
+
+It is currently possible to avoid this behavior to Unicode by setting `dataFrom.find.conversionStrategy: Unicode`. When using `Unicode`, any invalid character will be replaced by its unicode, in the form of `_UXXXX_`. In this case, the available kubernetes keys would be `a_c` and `a_U2215_c`, hence avoiding most of possible conflicts.
+
+!!! note "PRs welcome"
+    Some providers might not have the implementation needed for fetching multiple secrets. If that's your case, please feel free to contribute!

docs/snippets/getallsecrets-find-by-name.yaml

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+apiVersion: external-secrets.io/v1beta1 
+kind: ExternalSecret
+metadata:
+  name: find-by-tags
+spec:
+  refreshInterval: 1h
+  secretStoreRef:
+    name: secretstore-sample
+    kind: SecretStore
+  target:
+    name: secret-to-be-created
+  dataFrom:
+  - find:
+      name:
+        regexp: "key"

docs/snippets/getallsecrets-find-by-tags.yaml

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+apiVersion: external-secrets.io/v1beta1 
+kind: ExternalSecret
+metadata:
+  name: find-by-tags
+spec:
+  refreshInterval: 1h
+  secretStoreRef:
+    name: secretstore-sample
+    kind: SecretStore
+  target:
+    name: secret-to-be-created
+  dataFrom:
+  - find:
+      tags:
+        environment: "prod"
+        application: "app-name"

hack/api-docs/mkdocs.yml

@@ -41,6 +41,7 @@ nav:
     - All keys, One secret: guides-all-keys-one-secret.md
     - Common K8S Secret Types: guides-common-k8s-secret-types.md
     - Controller Classes: guides-controller-class.md
+    - Getting Multiple Secrets: guides-getallsecrets.md
     - Multi Tenancy: guides-multi-tenancy.md
     - Metrics: guides-metrics.md
     - Upgrading to v1beta1: guides-v1beta1.md