Consolidate chapter page data into single file (#144)

## Summary

* Consolidate chapter page data into single file
* Header structure of the file stays the same, following the page count,
we now put a LUT offset
   * The page data is all then appended to this file
* Finally the LUT is appended to the end of the file, and the page count
is updated
* This will also significantly improve the duration of cache cleanup
which takes a while to scan the directory and cleanup content
* Remove page file version as it's all tied up into the section file now
* Bumped section file version to 7
* Moved section content into sub directory
* Updated docs

## Additional Context

* Benchmarks:
  * Generating 74 pages of content from a chapter in Jade Legacy took:
    * master: 6,229ms
    * this PR: 1,305ms
    * Speedup of 79%
  * Generating 207 pages of content from Livesuit book:
    * With progress bar UI updates:
      * master: 24,250ms
      * this PR: 8,063ms
      * Speedup of 67%
    * Without progress bar UI updates:
      * master: 13,055ms
      * this PR: 3,600ms
      * Speedup of 72%

docs/file-formats.md

@@ -0,0 +1,9 @@
+# File Formats
+
+## `book.bin`
+
+![](./images/file-formats/book-bin.png)
+
+## `section.bin`
+
+![](./images/file-formats/section-bin.png)