Include dependencies in contributing doc, plus gitignore.

[robert-e-davidson3]

Description

I added a section describing the requirements to build and test cadence. Aside from go, wabt is also needed.

I also added some paths to .gitignore since they were generated when I ran make build or make test.

Notes:

• I didn't create an issue. Do I need to?
• Not sure which label(s) to use.

[github-actions]

Cadence Benchstat comparison

This branch with compared with the base branch onflow:master commit 056cce3
The command go test ./... -run=XXX -bench=. -shuffle=on -count N was used.
Bench tests were run a total of 7 times on each branch.

Results

	old.txt	new.txt
	time/op		delta
RuntimeFungibleTokenTransfer-2	1.29ms ± 3%	1.57ms ±18%	+21.89%	(p=0.001 n=7+7)
CheckContractInterfaceFungibleTokenConformance-2	170µs ± 2%	178µs ± 7%	+4.99%	(p=0.011 n=7+7)
RuntimeResourceDictionaryValues-2	16.8ms ± 3%	17.4ms ± 3%	+4.04%	(p=0.002 n=6+7)
RuntimeStorageWriteCached-2	168µs ±45%	143µs ± 2%	~	(p=0.456 n=7+7)
ParseArray-2	24.1ms ± 3%	23.5ms ± 4%	~	(p=0.073 n=7+7)
ParseInfix-2	25.2µs ± 1%	25.2µs ± 2%	~	(p=0.710 n=7+7)
ParseFungibleToken-2	493µs ± 1%	485µs ± 3%	~	(p=0.073 n=6+7)
ParseDeploy/byte_array-2	35.5ms ± 2%	35.3ms ± 1%	~	(p=0.259 n=7+7)
QualifiedIdentifierCreation/One_level-2	3.35ns ± 3%	3.30ns ± 0%	~	(p=0.300 n=7+7)
QualifiedIdentifierCreation/Three_levels-2	164ns ± 1%	164ns ± 1%	~	(p=0.836 n=6+7)
InterpretRecursionFib-2	2.78ms ± 2%	2.80ms ± 4%	~	(p=0.902 n=7+7)
NewInterpreter/new_interpreter-2	1.21µs ± 2%	1.21µs ± 5%	~	(p=1.000 n=7+7)
NewInterpreter/new_sub-interpreter-2	2.17µs ± 2%	2.17µs ± 1%	~	(p=0.945 n=7+6)
ParseDeploy/decode_hex-2	1.50ms ± 5%	1.44ms ± 1%	−4.17%	(p=0.001 n=7+6)
ContractInterfaceFungibleToken-2	51.1µs ± 1%	48.5µs ± 2%	−5.23%	(p=0.001 n=6+7)
	alloc/op		delta
RuntimeStorageWriteCached-2	83.7kB ± 0%	83.7kB ± 0%	~	(p=0.832 n=6+7)
RuntimeResourceDictionaryValues-2	4.34MB ± 0%	4.34MB ± 0%	~	(p=0.779 n=7+7)
RuntimeFungibleTokenTransfer-2	233kB ± 0%	233kB ± 0%	~	(p=0.805 n=7+7)
QualifiedIdentifierCreation/One_level-2	0.00B	0.00B	~	(all equal)
QualifiedIdentifierCreation/Three_levels-2	64.0B ± 0%	64.0B ± 0%	~	(all equal)
CheckContractInterfaceFungibleTokenConformance-2	66.4kB ± 0%	66.4kB ± 0%	~	(p=0.592 n=7+7)
ContractInterfaceFungibleToken-2	26.7kB ± 0%	26.7kB ± 0%	~	(all equal)
InterpretRecursionFib-2	1.21MB ± 0%	1.21MB ± 0%	~	(all equal)
NewInterpreter/new_interpreter-2	680B ± 0%	680B ± 0%	~	(all equal)
NewInterpreter/new_sub-interpreter-2	1.06kB ± 0%	1.06kB ± 0%	~	(all equal)
	allocs/op		delta
RuntimeStorageWriteCached-2	1.42k ± 0%	1.42k ± 0%	~	(all equal)
RuntimeResourceDictionaryValues-2	108k ± 0%	108k ± 0%	~	(p=0.446 n=7+6)
RuntimeFungibleTokenTransfer-2	4.43k ± 0%	4.42k ± 0%	~	(p=0.073 n=7+7)
QualifiedIdentifierCreation/One_level-2	0.00	0.00	~	(all equal)
QualifiedIdentifierCreation/Three_levels-2	2.00 ± 0%	2.00 ± 0%	~	(all equal)
CheckContractInterfaceFungibleTokenConformance-2	1.07k ± 0%	1.07k ± 0%	~	(all equal)
ContractInterfaceFungibleToken-2	458 ± 0%	458 ± 0%	~	(all equal)
InterpretRecursionFib-2	25.0k ± 0%	25.0k ± 0%	~	(all equal)
NewInterpreter/new_interpreter-2	11.0 ± 0%	11.0 ± 0%	~	(all equal)
NewInterpreter/new_sub-interpreter-2	31.0 ± 0%	31.0 ± 0%	~	(all equal)

[turbolent]

Nice! First PR 🎉👏