valid: Add Errorf function

Add an Errorf function to create GraphQL errors without a validation
context.

database: always include table name in SELECT

When JOINs are performed on the auto-generated SELECT query,
multiple tables may have the same field names. For instance, in
lists.sr.ht the "list" and "subscription" tables both have an "id"
column. When performing a "mailingLists" GraphQL query this results
in this error:

    pq: column reference "id" is ambiguous

The old query looks like this:

    SELECT "description", "name", "id", "owner_id", "updated", COALESCE(
    access.permissions,
    CASE WHEN list.owner_id = $1
    THEN $2
    ELSE CASE WHEN sub.id IS NOT NULL
    	THEN list.subscriber_permissions
    	ELSE null END
    END,
    list.nonsubscriber_permissions | list.account_permissions), access.id AS access_id, sub.id AS subscription_id FROM list LEFT JOIN access ON
    access.list_id = list.id AND
    access.user_id = $3 LEFT JOIN subscription sub ON
    sub.list_id = list.id AND
    sub.user_id = $4 WHERE list.owner_id = $5 ORDER BY "updated" DESC LIMIT 26

The new query looks like this:

    SELECT "description", "name", "list"."id", "list"."owner_id", "list"."updated", COALESCE(
    access.permissions,
    CASE WHEN list.owner_id = $1
    THEN $2
    ELSE CASE WHEN sub.id IS NOT NULL
    	THEN list.subscriber_permissions
    	ELSE null END
    END,
    list.nonsubscriber_permissions | list.account_permissions), access.id AS access_id, sub.id AS subscription_id FROM list LEFT JOIN access ON
    access.list_id = list.id AND
    access.user_id = $3 LEFT JOIN subscription sub ON
    sub.list_id = list.id AND
    sub.user_id = $4 WHERE list.owner_id = $5 ORDER BY "updated" DESC LIMIT 26

go fmt

webhooks: Add FilterWebhooks function

valid: add OptionalBool

Bugfix, mail config placed in wrong setting.

Replace x/crypto package by ProtonMail/go-crypto to support ed25519 OpenPGP keys

Add support for mail setups that don't support TLS or Auth

Allow AUTH_COOKIE to access @private fields

auth: fix nil reference in auth method check

Add @anoninternal support code

This is a slightly better approach to the previous commit.

webhooks: fix failing test

auth: implement internal anonymous authentication

This is used for meta.sr.ht's GraphQL user registration resolver, which
needs to run prior to the user's information being added to the database.

server/email: handle errors out of GQL context

webhooks/legacy: fetch subscriptions upfront

This fixes a race condition when delivering webhooks for resource
deletion events, in which the subscriptions would be removed from the
delete cascade before the task to fetch them executes. This requires the
downstream code to call Queue before committing the delete transaction,
and updates the API to include a context argument for the connection
pool.

server/email: include variables

server: move auth middlware ahead of RealIP

So that @internal auth can correctly test against internal-ipnet.

valid: fix nil values in OptionalString

valid: add generic optional interface

go fmt