Decrease memory consumption for 1.18.0

[gilberg-vrn]

This is:

• [x] improvement

Checklist:

• [x] Code style is respected
• [x] Commit message explains why the change is made (see https://github.com/erlang/otp/wiki/Writing-good-commit-messages)

Why this change is needed?

On write large tables (500k rows x 20+ cols) PhpSpreadsheet fails on extra memory allocation (checked on max_memory = 4G) With that PR we got:

• stringTable now use temporary file
• stringTable store inverted index in cache
• cells index rewrite for use 4-bytes blocks and Generator instead in-memory
• rewrite getHighest* methods in Cells
• XMLWriter now return resource instead file content when used STORAGE_DISK

[gilberg-vrn]

Can fix #2107

[vassil-velichkov]

Any progress on this PR?

[eigan]

@gilberg-vrn I opened #2529 with your changes from Cells. Put you as author of the commit. Please let me know if I should close it or whatever 🙂