Add ZStandard frame and dictionary types

Co-authored-by: adamhathcock <527620+adamhathcock@users.noreply.github.com>

src/SharpCompress/Compressors/ZStandard/Unsafe/ZSTD_ResetDirective.cs

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+namespace SharpCompress.Compressors.ZStandard.Unsafe;
+
+public enum ZSTD_ResetDirective
+{
+    ZSTD_reset_session_only = 1,
+    ZSTD_reset_parameters = 2,
+    ZSTD_reset_session_and_parameters = 3,
+}

src/SharpCompress/Compressors/ZStandard/Unsafe/ZSTD_dictContentType_e.cs

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+namespace SharpCompress.Compressors.ZStandard.Unsafe;
+
+public enum ZSTD_dictContentType_e
+{
+    /// <summary>dictionary is "full" when starting with ZSTD_MAGIC_DICTIONARY, otherwise it is "rawContent"</summary>
+    ZSTD_dct_auto = 0,
+
+    /// <summary>ensures dictionary is always loaded as rawContent, even if it starts with ZSTD_MAGIC_DICTIONARY</summary>
+    ZSTD_dct_rawContent = 1,
+
+    /// <summary>refuses to load a dictionary if it does not respect Zstandard's specification</summary>
+    ZSTD_dct_fullDict = 2,
+}

src/SharpCompress/Compressors/ZStandard/Unsafe/ZSTD_dictLoadMethod_e.cs

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+namespace SharpCompress.Compressors.ZStandard.Unsafe;
+
+public enum ZSTD_dictLoadMethod_e
+{
+    /// <summary>Copy dictionary content internally</summary>
+    ZSTD_dlm_byCopy = 0,
+
+    /// <summary>Reference dictionary content -- the dictionary buffer must outlive its users</summary>
+    ZSTD_dlm_byRef = 1,
+}

src/SharpCompress/Compressors/ZStandard/Unsafe/ZSTD_frameHeader.cs

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+namespace SharpCompress.Compressors.ZStandard.Unsafe;
+
+public struct ZSTD_frameHeader
+{
+    /// <summary>if == ZSTD_CONTENTSIZE_UNKNOWN, it means this field is not available. 0 means "empty"</summary>
+    public ulong frameContentSize;
+
+    /// <summary>can be very large, up to frameContentSize</summary>
+    public ulong windowSize;
+    public uint blockSizeMax;
+
+    /// <summary>if == ZSTD_skippableFrame, frameContentSize is the size of skippable content</summary>
+    public ZSTD_frameType_e frameType;
+    public uint headerSize;
+
+    /// <summary>for ZSTD_skippableFrame, contains the skippable magic variant [0-15]</summary>
+    public uint dictID;
+    public uint checksumFlag;
+    public uint _reserved1;
+    public uint _reserved2;
+}

src/SharpCompress/Compressors/ZStandard/Unsafe/ZSTD_frameType_e.cs

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+namespace SharpCompress.Compressors.ZStandard.Unsafe;
+
+public enum ZSTD_frameType_e
+{
+    ZSTD_frame,
+    ZSTD_skippableFrame,
+}