Enable CodeQL analysis

[johnsonjh]

• Actually a very useful service and free for open-source

[johnsonjh]

• Verified clean merge with recursive strategy against develop as of Thu Nov 26 02:01:32 PM EST 2020 + PR Improvement in bbolt/walletdb speed #111 + PR More reliably detect if we are current (or not.) #142 + PR Fix bug where pktctl -h would show help twice. #151 + PR blockchain: Avoid deadlock with additional locking #156 + PR peer: Default to 1s default trickle interval #160 + PR Optimization: Compare strings to a null string directly #168 + PR Fix cookie authentication; always show version information #175 + PR btcutil/hdkeychain/extendedkey.go: Fix a typo. #185 + PR Remove TTY detection #201 + PR peer/peer_test: Fix race conditions in peer test. #212 + PR README: Overhaul the text, include badges, links, etc. #220 + PR Update Travis to DPLv2: Move to Go 1.15.5, Focal & Catalina, Coveralls.io enabled, etc. #222 + PR Quiet some errors and warnings #223 + PR Add .revive.config.toml: Revive configuration file #224 + PR Use strictly compliant MD list item formatting #228 + PR Unmodularize GoLevelDB + use build tags for tests. #229

Merge made by the 'recursive' strategy.
 .github/workflows/codeql-analysis.yml | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 .github/workflows/codeql-analysis.yml

[johnsonjh]

CodeQL no longer allows processing forked repositories, which makes it rather useless for our purposes, closing PR.