move pack library docs to libpack.md

doc/en/scripting/builtins/libpack.md

@@ -0,0 +1,97 @@
+# *pack* library
+
+```python
+pack.is_installed(packid: str) -> bool
+```
+
+Check if specified pack is installed in the world
+
+```lua
+pack.data_file(packid: str, filename: str) -> str
+-- and
+pack.shared_file(packid: str, filename: str) -> str
+```
+
+Returns the path to the data file
+and creates missing directories in the path.
+
+- The first option returns: `world:data/packid/filename`
+- The second option returns: `config:packid/filename`
+
+Examples:
+```lua
+file.write(pack.data_file(PACK_ID, "example.txt"), text)
+```
+For a *containermod* pack, write text to `world:data/containermod/example.txt`.
+
+Use this to store in-world data.
+
+```lua
+file.write(pack.shared_file(PACK_ID, "example.txt"), text)
+```
+For a *containermod* pack, write text to `config:containermod/example.txt`
+
+Use this to store shared data for all worlds.
+
+```python
+pack.get_folder(packid: str) -> str
+```
+
+Returns the path to the folder of the installed content pack.
+
+Example:
+```lua
+file.write(pack.data_file(PACK_ID, "example.txt"), text)
+```
+
+For pack *containermod* will write text to the file `world:data/containermod/example.txt`
+
+```python
+pack.get_folder(packid: str) -> str
+```
+
+Returns installed content-pack folder.
+
+```python
+pack.is_installed(packid: str) -> bool
+```
+
+Check if the world has specified pack installed.
+
+```python
+pack.get_installed() -> strings array
+```
+
+Returns all installed content-pack ids.
+
+```python
+pack.get_available() -> strings array
+```
+
+Returns the ids of all content packs available but not installed in the world.
+
+```python
+pack.get_base_packs() -> strings array
+```
+
+Returns the id of all base packages (non-removeable)
+
+```python
+pack.get_info(packid: str) -> {
+  id: str,
+  title: str,
+  creator: str,
+  description: str,
+  version: str,
+  icon: str,
+  dependencies: optional strings array
+}
+```
+
+Returns information about the pack (not necessarily installed).
+- icon - name of the preview texture (loading automatically)
+- dependencies - strings following format `{lvl}{id}`, where lvl:
+  - `!` - required
+  - `?` - optional
+  - `~` - weak
+  for example `!teal`