Submission of varops budget and tapscript leaf 0xc2 BIPS (aka "Script Restoration") for BIP numbers.

[Rusty Russell]

Hi all,

I've submitted a PR to the BIPs repo to merge the first two
drafts of the previously posted[1] "A Bitcoin Scripting Proposal BIP
Quartet":

https://github.com/bitcoin/bips/pull/2118

The only substantive change since the last discussion is that the costs
have increased for some operations (hashing and copying bytes), as a
result of benchmarking on a wider array of machines[2]. This follows our
conservative approach to make the worst-case validation times no worse
than they are presently, on any viable hardware.

The remaining two BIPs (OP_TX, and new opcodes) are not submitted: they
are mainly useful to provide a roadmap what functional gaps remain after
the script extensions, and do not have full implementations.

Cheers!
Rusty & Julian.

[1] https://groups.google.com/g/bitcoindev/c/GisTcPb8Jco/m/8znWcWwKAQAJ
[2] https://github.com/jmoik/varopsData