For https://github.com/turt2live/matrix-media-repo/issues/15

Fixes https://github.com/turt2live/matrix-media-repo/issues/239
Fixes https://github.com/turt2live/matrix-media-repo/issues/253

Bumps [lodash](https://github.com/lodash/lodash) from 4.17.15 to 4.17.19.
- [Release notes](https://github.com/lodash/lodash/releases)
- [Commits](https://github.com/lodash/lodash/compare/4.17.15...4.17.19

)

Signed-off-by: dependabot[bot] <support@github.com>

In various places in the code base, the address and port are joined using a `:`.
This causes issues with IPv6-addresses (see #247).
Address this by using net.JoinHostPort everywhere.

Signed-off-by: Silke Hofstra <silke@slxh.eu>

Resolves #244

Signed-off-by: Silke Hofstra <silke@slxh.eu>

This removes a select across the whole table by ensuring we generate a media ID which is highly unlikely to conflict with the database.