Increased RAM size for debugging

[mchack-work]

When debugging it's often useful to run an unoptimized program or add extra code which might not always fit in the 128 k RAM we currently have on the platform.

We have some experimental code that increases the RAM in qemu, the firmware, tkey-libs to be able to use this.

Let's discuss all of them and how they fit together in this issue.

• qemu PR: Increase the RAM size to 1 MB for debugging #39
  The original PR just sets the memory to 1 MB, no questions asked. In the discussion it's suggested to piggyback on the -m flag in qemu and be able to set this dynamically.
• tkey-libs: Change TKey RAM and APP mem size for QEMU build tkey-libs#71
• firmware: Change size of TKey memory in QEMU to be able to debug large apps tillitis-key1#363

Will also need changes to, at least, the tkeyclient Go package which has a check for how large the app is.