feat(parachain/availabilitystore): implement database access functions for availability store subsystem

[edwardmack]

Changes

This PR introduces code for handle database access for the availability store subsystem to enable write, read and delete of data to persistent storage.

Tests

go test github.com/ChainSafe/gossamer/dot/parachain/availability-store

Issues

closes: #3628

Primary Reviewer

@kishansagathiya @axaysagathiya

[kishansagathiya]

Right now, if you try to build this directly it won't

kishan@kishan-Inspiron-14-7425-2-in-1:~/code/gossamer$ make gossamer 
rm -fr ./bin
  >  Building binary... 
go build -trimpath -o ./bin/gossamer -ldflags="-s -w" ./cmd/gossamer
# github.com/ChainSafe/gossamer/cmd/gossamer
/usr/local/go/pkg/tool/linux_amd64/link: running gcc failed: exit status 1
/usr/bin/ld: cannot find -lerasure: No such file or directory
collect2: error: ld returned 1 exit status

make: *** [Makefile:80: build] Error 1

You will have to build the erasure lib first

cargo build --release --manifest-path=lib/erasure/rustlib/Cargo.toml

and then call make gossamer, which would work.

Let's add this into our ci workflows so that CI dont fail. Right now, this is what is causing CI fails in this PR.

[kishansagathiya]

Most of structs, methods in this package will likely not get used outside. Unless we have to scale encode or decode them, let's unexport them. I have pointed only at a few places, but there are many other places as well.

[kishansagathiya]

There are files that are being autogenerated inside lib/erasure/rustlib. Put them in .gitignore.

[kishansagathiya]

There are files that are being autogenerated inside lib/erasure/rustlib. Put them in .gitignore.

My bad. lib/erasure/rustlib/target is the only part that is auto-generated. I was mistaken because I was checking out into developement which doesn't have lib/erasure/rustlib/target in gitignore, so It was showing them under untracked files. All good.

[EclesioMeloJunior]

LGTM