Add an FAQ to docs (#1428)

## Description

Covers some questions that have come up in initial user testing

## Type of change

- [x] 🗺️ Documentation

## Test Plan

<!-- How will this be tested prior to merging.-->
- [x] 💪 Manual

docs/.markdownlint.json

@@ -11,7 +11,9 @@
             "Tabs",
             "TabItem",
             "CodeBlock",
-            "DownloadBinaries"
+            "DownloadBinaries",
+            "details",
+            "summary"
         ]
     },
 }

docs/docs/support/faq.md

@@ -0,0 +1,22 @@
+# FAQ
+
+<details>
+    <summary>Where does Corso store local configuration?</summary>
+
+Corso's local configuration is stored in a file named `.corso.toml` in your home directory. Corso can be pointed at
+separate configuration files using the `--config-file` option.
+
+</details>
+
+<details>
+    <summary>Does Corso report usage telemetry?</summary>
+
+In order to better understand how people use Corso and to guide feature development, Corso supports reporting telemetry
+metadata for basic information about installed versions and usage in a privacy-preserving manner. This includes a
+generic description of most-commonly used backup operations and statistics on the duration and size of backups. No user
+data is stored or transmitted during this process.
+
+Telemetry reporting can be turned off by using the `--no-stats` flag. See the [Command Line Reference](cli/corso)
+section for more information.
+
+</details>

docs/sidebars.js

@@ -42,7 +42,7 @@ const sidebars = {
       type: 'category',
       label: 'Support',
       items: [
-        'support/bugs_and_features', 'support/known_issues'
+        'support/bugs_and_features', 'support/known_issues', 'support/faq'
       ],
     },
     {